Graphite thermoelectric and/or resistive thermal management systems and methods

ABSTRACT

Disclosed embodiments include thermal management systems and methods configured to heat and/or cool an electrical device. Thermal management systems can include a heat spreader in thermal communication with a temperature sensitive region of the electrical device. The heat spreader can include the one or more pyrolytic graphite sheets. The heat spreader can include thermal/electrical elevators connecting the one or more pyrolytic graphite sheets. The systems can include a thermoelectric device in thermal communication with the heat spreader. Electric power can be directed to the heat spreader and/or thermoelectric device to provide controlled heating and/or cooling of the electrical device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119(e) of U.S.Provisional Application No. 62/050,001, filed Sep. 12, 2014, titledINTEGRATED GRAPHITE THERMOELECTRIC AND RESISTIVE THERMAL MANAGEMENTDEVICE AND METHODS, the entirety of which is incorporated herein byreference and made a part of this specification.

BACKGROUND

Field

The present disclosure relates generally to thermal management (e.g.,heating and/or cooling) of electrical devices including but not limitedto batteries.

Description of Related Art

Power electronics and other electrical devices, such as batteries, canbe sensitive to overheating, cold temperatures, extreme temperatures,and operating temperature limits. The performance of such devices may bediminished, sometimes severely, when the devices are operated outside ofrecommended temperature ranges. In semiconductor devices, integratedcircuit dies can overheat and malfunction. In batteries, including, forexample, batteries used for automotive applications in electrified orelectrical vehicles, battery cells and their components can degrade whenoverheated or overcooled. Such degradation can manifest itself inreduced battery storage capacity and/or reduced ability for the batteryto be recharged over multiple duty cycles.

High performance batteries for use in large systems (including, forexample, lithium based batteries used in electrical vehicles) havecertain properties that make thermal management of the batteries and/orcontainment system desirable. Charging characteristics of highperformance batteries change at elevated temperatures and can cause thecycle life of the batteries to decrease significantly if they arecharged or discharged at a temperature outside of an optimum range(e.g., too high or too low of a temperature). For example, the cyclelife of some lithium based batteries decreased by over 50% if they arerepeatedly charged at about 50° C. Since cycle life can be reduced by alarge amount, the lifetime cost of batteries can be greatly increased ifcharging temperatures are not controlled within proper limits. Also,some high performance batteries can exhibit reduced performance and canbe possibly damaged if charged or operated at too low of temperatures,such as below about −30° C. Furthermore, high performance batteries andarrays of high performance batteries can experience thermal events fromwhich the batteries can be permanently damaged or destroyed, and overtemperature condition can even result in fires and other safety relatedevents.

This background is provided to introduce a brief context for the Summaryand Detailed Description that follow. This Background is not intended tobe viewed as limiting the claimed subject matter to implementations thatsolve any or all of the disadvantages or problems presented herein.

SUMMARY

It can be advantageous to manage the thermal conditions of powerelectronics and other electrical devices. Thermal management can reduceincidences of overheating, overcooling, and electrical devicedegradation. Certain embodiments described herein provide thermalmanagement of devices that carry significant electric power and/orrequire high current and efficiency (e.g., power amplifiers,transistors, transformers, power inverters, insulated-gate bipolartransistors (IGBTs), electric motors, high power lasers andlight-emitting diodes, batteries, and others). A wide range of solutionscan be used to thermally manage such devices, including convective airand liquid cooling, conductive cooling, spray cooling with liquid jets,thermoelectric cooling of boards and chip cases, and other solutions. Atleast some embodiments disclosed herein provide at least one of thefollowing advantages compared to existing techniques for heating orcooling electrical devices: higher power efficiency, lower or eliminatedmaintenance costs, greater reliability, longer service life, fewercomponents, fewer or eliminated moving parts, heating and cooling modesof operation, other advantages, or a combination of advantages.

Disclosed is an electrical device thermal management system. In someembodiments, the electrical device is a battery. A battery thermalmanagement system can include one or more heat spreaders positionedbetween stacked battery cells. The one or more heat spreaders may haveone or more pyrolytic graphite sheets that can function as a heaterand/or cooler. In a heating mode of the battery thermal managementsystem, electric current may flow through a heat spreader (e.g., throughthe graphite sheets and/or a substrate) such that the heat spreaderfunctions as a resistance heater. In a cooling mode of the batterythermal management system, the heat spreader can transfer heat away fromthe battery cells to a heat sink.

In some embodiments, one or more thermoelectric devices can be attachedto the one or more heat spreaders. In the heating mode, the one or morethermoelectric devices can transfer heat from a heat source into the oneor more heat spreaders that transfer heat into the battery cells. In acooling mode, the one or more thermoelectric devices can transfer heatto a heat sink from the one or more heat spreaders that transfer heatfrom the battery cells.

In some embodiments, one or more thermal/electrical connectors can bepositioned between graphite sheets of a heat spreader (e.g.thermal/electrical connectors extending orthogonal to a plane extendingsubstantially parallel to the graphite sheets). The one or morethermal/electrical connectors transfer heat or electrons between layersof graphite sheets (e.g. orthogonal to the parallel plane) to enhancethermal/electrical efficiency of the heat spreader. The heat spreadercan include one or more connections to other components of theelectrical device and/or thermal management system. The one or moreconnections of the heat spreader can include thermal/electricalconnectors to enhance thermal/electrical communication efficiency of theheat spreader with other components of the system.

According to this disclosure, a thermoelectric battery thermalmanagement system configured to manage temperature of a battery cellincludes one or more the following: a heat spreader in thermalcommunication with a temperature sensitive region of a battery cell; athermoelectric device comprising a main side and a waste side, thethermoelectric device configured to transfer thermal energy between themain side and the waste side of the thermoelectric device uponapplication of electric current to the thermoelectric device; the mainside of the thermoelectric device is in thermal communication with theheat spreader to heat or cool the battery cell by adjusting a polarityof electric current delivered to the thermoelectric device; and/or athermal management controller configured to operate in a heating mode ora cooling mode. The heat spreader includes one or more of the following:pyrolytic graphite in thermal communication with the temperaturesensitive region of the battery cell, the pyrolytic graphite comprisinga plurality of graphite layers extending substantially in parallel alongthe heat spreader and configured to transfer thermal energy and electriccurrent along a plane substantially parallel to the graphite layers; aplurality of thermal elevators between the plurality of graphite layers,the thermal elevators configured to transfer thermal energy between theplurality of graphite layers and configured to transfer thermal energysubstantially orthogonal to the plane; and/or a conductor in thermalcommunication with the pyrolytic graphite and the plurality of thermalelevators, the conductor in electrical communication with the pyrolyticgraphite to heat the battery cell upon application of electric currentthrough the pyrolytic graphite via the conductor. In the heating mode,the battery cell is heated by the heat spreader transferring thermalenergy to the temperature sensitive region of the battery cell whenelectric current is applied to the heat spreader via the conductor, whenelectric current is applied to the thermoelectric device in a firstpolarity, or when electric current is applied to both the heat spreadervia the conductor and the thermoelectric device in the first polarity.In the cooling mode, the battery cell is cooled by the heat spreadertransferring thermal energy away from the temperature sensitive regionof the battery cell when electric current is applied to thethermoelectric device in a second polarity.

In some embodiments, the thermoelectric battery thermal managementsystem further includes one or more of the following: the heat spreadercomprises a first side and a second side, the first side substantiallyopposite the second side; the heat spreader comprises an other conductorin thermal and electrical communication with the pyrolytic graphite onthe second side of the heat spreader, the conductor on the first side ofthe heat spreader; in the heating mode, the battery cell is heated whenelectric current is applied to the pyrolytic graphite via the conductorand the other conductor such that electric current flows along theplurality of graphite layers from the first side to the second side ofthe heat spreader; the other conductor comprises an electrical junctionconfigured to electrically connect to a printed circuit board comprisingthe thermal management controller, the electrical junction configured todeliver electric current to the heat spreader; the battery cell and theheat spreader are positioned in a battery case; the conductor isconfigured to attach to the battery case to physically fix the heatspreader relative to the battery case; a thermal interface on thebattery case and configured to mate with the conductor; the conductorcomprises a first mechanical connector; the thermal interface comprisesa second mechanical connector configured to mate with the firstmechanical connector to attach the conductor to the battery case; thefirst mechanical connector comprises a male dovetail connector and thesecond mechanical connector comprises a female dovetail connectorconfigured to accept the male dovetail connector to attach the conductorto the battery case; the battery case comprises a thermal windowconfigured to transfer thermal energy in and out of the battery case,the thermal window in thermal communication with the thermal interface;the battery case comprises a thermal substrate in the thermal window,the thermal substrate configured to transfer thermal energy in and outof the battery case while providing a physical barrier into the batterycase; the main side of the thermoelectric device is in thermalcommunication with the thermal substrate to provide the thermalcommunication between the main side of the thermoelectric device and theheat spreader via the conductor and the thermal interface; thethermoelectric device is positioned outside of the battery case; ablower and duct assembly attached to the battery case and configured topush or pull air across the waste side of the thermoelectric device; thethermal management controller is configured to optimize systemefficiency such that airflow from a blower of the blower and ductassembly is increased or decreased to match heating or coolingrequirements of the battery cell; a blower and duct assembly in thermalcommunication with the thermoelectric device and configured to push orpull air across the waste side of the thermoelectric device; the thermalmanagement controller is configured to optimize system efficiency suchthat airflow from a blower of the blower and duct assembly is increasedor decreased to match heating or cooling requirements of the batterycell; the waste side of the thermoelectric device is in thermalcommunication with air via a waste heat exchanger; the waste side of thethermoelectric device comprises the waste heat exchanger; the heatspreader comprises a plurality of breaks in the plurality of graphitelayers, the plurality of breaks configured to increase a conduction pathfor electric current through the heat spreader to increase resistiveheating capacity of the heat spreader; the plurality of graphite layersare crinkled to increase a length of a surface of at least one graphitelayer of the plurality of graphite layers, the increased length of thesurface of the at least one graphite layer configured to increase aconduction path for electric current through the at least one graphitelayer to increase resistive heating capacity of the heat spreader; theconductor comprises at least some of the plurality of thermal elevatorssuch that the plurality of thermal elevators is substantially on ends ofthe heat spreader; the heat spreader is in thermal communication with atemperature sensitive region of an other battery cell on a side of theheat spreader opposite a side of the heat spreader in thermalcommunication with the temperature sensitive region of the battery cell;at least some of the plurality of thermal elevators extend substantiallya length between the sides of the heat spreader in thermal communicationwith the temperature sensitive regions of the battery cell and the otherbattery cell; the at least some of the plurality of thermal elevatorsextending between the sides of the heat spreader are in direct thermalcommunication with the battery cell and the other battery cell to reducethermal contact resistance associated with the heat spreader; theplurality of thermal elevators comprises a metallic material configuredto transfer electric current between the plurality of graphite layersand the conductor; and/or the conductor extends substantially anentirety of a dimension of the heat spreader to provide structuralintegrity to the heat spreader.

According to this disclosure, a battery thermal management systemconfigured to heat or cool a battery cell includes one or more of thefollowing: a heat spreader in thermal communication with a battery cell;and/or a thermoelectric device comprising a main side and a waste side,the thermoelectric device configured to transfer thermal energy betweenthe main side and the waste side of the thermoelectric device uponapplication of electric current to the thermoelectric device; the mainside of the thermoelectric device is in thermal communication with theheat spreader to heat or cool the battery cell by adjusting a polarityof electric current delivered to the thermoelectric device. The heatspreader includes one or more the following: a pyrolytic graphite sheetconfigured to transfer thermal energy and electric current along thepyrolytic graphite sheet; and/or a conductor in thermal and electricalcommunication with the pyrolytic graphite sheet, the conductor inelectrical communication with the pyrolytic graphite sheet to heat thebattery cell upon application of electric current to the pyrolyticgraphite sheet via the conductor, the conductor in thermal communicationwith the pyrolytic graphite sheet to transfer thermal energy to and fromthe pyrolytic graphite sheet. The battery cell is heated by the heatspreader transferring thermal energy to the battery cell when electriccurrent is applied to the heat spreader via the conductor, or whenelectric current is applied to the thermoelectric device in a firstpolarity, or when electric current is applied to both the heat spreadervia the conductor and the thermoelectric device in the first polarity.The battery cell is cooled by the heat spreader transferring thermalenergy away from the battery cell when electric current is applied tothe thermoelectric device in a second polarity.

In some embodiments, the battery thermal management system furtherincludes one or more of the following: the heat spreader comprises afirst side and a second side, the first side substantially opposite thesecond side; the heat spreader comprises an other conductor in thermaland electrical communication with the pyrolytic graphite sheet; thebattery cell is heated when electric current is applied to the pyrolyticgraphite sheet via the conductor and the other conductor such thatelectric current flows along the pyrolytic graphite sheet from the firstside to the second side of the heat spreader; the other conductorcomprises an electrical junction configured to electrically connect to aprinted circuit board, the electrical junction configured to deliverelectric current to the heat spreader; the battery cell and the heatspreader are positioned in a battery enclosure; the conductor isconfigured to connect with the battery enclosure to secure the heatspreader to the battery enclosure; a thermal interface on the batteryenclosure and configured to mate with the conductor; the conductorcomprises a first mechanical connector; the thermal interface comprisesa second mechanical connector configured to mate with the firstmechanical connector to attach the conductor to the battery enclosure;the first mechanical connector comprises a male dovetail connector andthe second mechanical connector comprises a female dovetail connectorconfigured to accept the male dovetail connector to attach the conductorto the battery enclosure; the battery enclosure comprises a thermalwindow configured to transfer thermal energy in and out of the batteryenclosure; the battery enclosure comprises a thermal substrate in thethermal window, the thermal substrate configured to transfer thermalenergy in and out of the battery enclosure while providing a physicalbarrier into the battery enclosure; the thermoelectric device is inthermal communication with the thermal substrate to provide the thermalcommunication between the thermoelectric device and the heat spreader;the thermoelectric device is positioned outside of the batteryenclosure; a blower and duct assembly attached to the battery enclosureand configured to push or pull air across the waste side of thethermoelectric device; a blower of the blower and duct assembly isconfigured to optimize system efficiency such that airflow is increasedor decreased to match heating or cooling requirements of the batterycell; a blower and duct assembly in thermal communication with thethermoelectric device and configured to push or pull air across thewaste side of the thermoelectric device; a blower of the blower and ductassembly is configured to optimize system efficiency such that airflowis increased or decreased to match heating or cooling requirements ofthe battery cell; the waste side of the thermoelectric device is inthermal communication with air via a waste heat exchanger; the wasteside of the thermoelectric device comprises the waste heat exchanger;the heat spreader comprises a break in the pyrolytic graphite sheet, thebreak configured to increase a travel path for electric current throughthe heat spreader to increase resistive heating capacity of the heatspreader; the pyrolytic graphite sheet is crinkled to increase a lengthof a surface of the pyrolytic graphite sheet, the increased length ofthe surface of the pyrolytic graphite sheet configured to increase atravel path for electric current through the pyrolytic graphite sheet toincrease resistive heating capacity of the heat spreader; the conductorextends substantially an entirety of a dimension of the heat spreader toprovide structural integrity to the heat spreader; the heat spreaderfurther comprises at least one other pyrolytic graphite sheet in thermaland electrical communication with the conductor, the at least one otherpyrolytic graphite sheet extending substantially in parallel with thepyrolytic graphite sheet; the conductor is in electrical communicationwith the at least one other pyrolytic graphite sheet to heat the batterycell upon application of electric current to the at least one otherpyrolytic graphite sheet via the conductor, the conductor in thermalcommunication with the at least one other pyrolytic graphite sheet totransfer thermal energy to and from the at least one other pyrolyticgraphite sheet; the heat spreader further comprises a thermal connectorbetween the pyrolytic graphite sheet and the at least one otherpyrolytic graphite sheet, the thermal connector configured to transferthermal energy between the pyrolytic graphite sheet and the at least oneother pyrolytic graphite sheet; the conductor comprises the thermalconnector; the thermal connector comprises a metallic materialconfigured to transfer electric current between the pyrolytic graphitesheet and the at least one other pyrolytic graphite sheet; the heatspreader is in thermal communication with an other battery cell on aside of the heat spreader opposite a side of the heat spreader inthermal communication with the battery cell; the thermal connector ispositioned between the sides of the heat spreader in thermalcommunication with the battery cell and the other battery cell; thethermal connector is in direct thermal communication with the batterycell and the other battery cell to reduce thermal contact resistanceassociated with the heat spreader; the heat spreader further comprises ametallic substrate in thermal communication with the pyrolytic graphitesheet; the pyrolytic graphite sheet is in thermal communication with thebattery cell such that the pyrolytic graphite sheet functions as thermalinterface between the battery cell and the metallic substrate; thepyrolytic graphite sheet extends along a surface of the metallicsubstrate on at least two sides of the metallic substrate; the pyrolyticgraphite sheet extends at least half a cross-sectional perimeter of themetallic substrate; the main side of the thermoelectric device ispositioned over at least a portion of the metallic substrate; thepyrolytic graphite sheet extends to be between the main side of thethermoelectric device and the metallic substrate to provide a thermalinterface between the thermoelectric device and the metallic substrate,the thermal interface configured to transfer thermal energy between themain side of the thermoelectric device and the metallic substrate; thebattery cell is heated by the heat spreader transferring thermal energyto the battery cell when electric current is applied to metallicsubstrate via the conductor; and/or the battery is cooled by the heatspreader transferring thermal energy away from the battery cell via thepyrolytic graphite sheet and the conductor when electric current isapplied to the thermoelectric device in the second polarity.

According to this disclosure, a heat spreader assembly for managingtemperature of an electrical device includes one or more of thefollowing: a graphite sheet in thermal communication with an electricaldevice, the graphite sheet configured to transfer thermal energy andelectric current along the graphite sheet; and/or a conductor in thermaland electrical communication with the graphite sheet, the conductor inelectrical communication with the graphite sheet to heat the electricaldevice upon application of electric current to the graphite sheet viathe conductor, the conductor in thermal communication with the graphitesheet to transfer thermal energy to and from the graphite sheet. Theelectrical device is heated by the graphite sheet transferring thermalenergy to the electrical device when electric current is applied to theheat spreader via the conductor. The electrical device is cooled by thegraphite sheet transferring thermal energy away from the electricaldevice.

In some embodiments, the heat spreader assembly further includes one ormore the following: an other conductor in thermal and electricalcommunication with the graphite sheet; the electrical device is heatedwhen electric current is applied to the graphite sheet via the conductorand the other conductor such that electric current flows along thegraphite sheet; the graphite sheet comprises a first side and a secondside, the first side substantially opposite the second side; theconductor is on the first side, and the other conductor is on the secondside; the other conductor comprises an electrical junction configured toelectrically connect to a printed circuit board comprising a controllerconfigured to manage temperature of the electrical device, theelectrical junction configured to deliver electric current to the heatspreader; the heat spreader assembly is positioned in an electricaldevice enclosure; the conductor is configured to connect with theelectrical device enclosure to secure the heat spreader assembly to theelectrical device enclosure; a thermal interface on the electricaldevice enclosure and configured to mate with the conductor; theconductor comprises a first mechanical connector; the thermal interfacecomprises a second mechanical connector configured to mate with thefirst mechanical connector to attach the conductor to the electricaldevice enclosure; the first mechanical connector comprises a maledovetail connector and the second mechanical connector comprises afemale dovetail connector configured to accept the male dovetailconnector to attach the conductor to the electrical device enclosure;the electrical device enclosure comprises a thermal window configured totransfer thermal energy in and out of the electrical device enclosure;the electrical device enclosure comprises a thermal substrate in thethermal window, the thermal substrate configured to transfer thermalenergy in and out of the electrical device enclosure while providing aphysical barrier into the electrical device enclosure; a thermoelectricdevice is in thermal communication with the thermal substrate to provideheating or cooling to the electrical device via the heat spreader; thethermoelectric device is positioned outside of the electrical deviceenclosure; a thermoelectric device is in thermal communication with thegraphite sheet; the electrical device by the graphite sheet whenelectric current is applied to the thermoelectric device in a firstpolarity; the electrical device is cooled by the graphite sheet whenelectric current is applied to the thermoelectric device in a secondpolarity; the graphite sheet comprises a break in covalent bonds in thegraphite sheet, the cut configured to increase a travel path forelectric current through the graphite sheet to increase resistiveheating capacity of the graphite sheet; the graphite sheet is crinkledto increase a length of the graphite sheet, the increased length ofgraphite sheet configured to increase a travel path for electric currentthrough the graphite sheet to increase resistive heating capacity of thegraphite sheet; the conductor extends substantially an entirety of adimension of the graphite sheet to provide structural integrity to thegraphite sheet; at least one other graphite sheet in thermal andelectrical communication with the conductor; the conductor is inelectrical communication with the at least one other graphite sheet toheat the electrical device upon application of electric current to theat least one other graphite sheet via the conductor, the conductor inthermal communication with the at least one other graphite sheet totransfer thermal energy to and from the at least one other graphitesheet; the graphite sheet and the at least one other graphite extendsubstantially in parallel in the heat spreader assembly; a thermalconnector between the graphite sheet and the at least one other graphitesheet, the thermal connector configured to transfer thermal energybetween the graphite sheet and the at least one other graphite sheet;the conductor comprises the thermal connector; the thermal connectorcomprises a metallic material configured to transfer electric currentbetween the graphite sheet and the at least one other graphite sheet; ametallic substrate in thermal communication with the graphite sheet; thegraphite sheet is in thermal communication with the electrical devicesuch that the graphite sheet is configured to transfer thermal energybetween the main side of the thermoelectric device and the metallicsubstrate; the graphite sheet extends along a surface of the metallicsubstrate on at least two sides of the metallic substrate; the graphitesheet extends at least half a cross-sectional perimeter of the metallicsubstrate; the electrical device is heated when electric current isapplied to metallic substrate via the conductor; the graphite sheetcomprises one or more pyrolytic graphite layers; the electrical devicecomprises a battery cell; and/or the graphite sheet is in thermalcommunication with a temperature sensitive region of the electricaldevice.

According to this disclosure, a method of manufacturing a batterythermal management system for heating or cooling a battery cell includesone or more of the following: thermally connecting a heat spreader to abattery cell; and/or thermally connecting a main side of athermoelectric device to the heat spreader to heat or cool the batterycell by adjusting a polarity of electric current delivered to thethermoelectric device, the thermoelectric device configured to transferthermal energy between the main side and a waste side of thethermoelectric device upon application of electric current to thethermoelectric device. The heat spreader includes one or more of thefollowing: a pyrolytic graphite sheet configured to transfer thermalenergy and electric current along the pyrolytic graphite sheet; and/or aconductor in thermal and electrical communication with the pyrolyticgraphite sheet, the conductor in electrical communication with thepyrolytic graphite sheet to heat the battery cell upon application ofelectric current to the pyrolytic graphite sheet via the conductor, theconductor in thermal communication with the pyrolytic graphite sheet totransfer thermal energy to and from the pyrolytic graphite sheet. Thebattery cell is heated by the heat spreader transferring thermal energyto the battery cell when electric current is applied to the heatspreader via the conductor, or when electric current is applied to thethermoelectric device in a first polarity, or when electric current isapplied to both the heat spreader via the conductor and thethermoelectric device in the first polarity. The battery cell is cooledby the heat spreader transferring thermal energy away from the batterycell when electric current is applied to the thermoelectric device in asecond polarity.

In some embodiments, the method of manufacturing a battery thermalmanagement system further includes one or more of the following: theheat spreader comprises a first side and a second side, the first sidesubstantially opposite the second side; the heat spreader comprises another conductor in thermal and electrical communication with thepyrolytic graphite sheet; the battery cell is heated when electriccurrent is applied to the pyrolytic graphite sheet via the conductor andthe other conductor such that electric current flows along the pyrolyticgraphite sheet from the first side to the second side of the heatspreader; the other conductor comprises an electrical junctionconfigured to electrically connect to a printed circuit board, theelectrical junction configured to deliver electric current to the heatspreader; positioning the battery cell and the heat spreader in abattery enclosure and connecting the conductor with the batteryenclosure to secure the heat spreader to the battery enclosure;connecting a thermal interface to the battery enclosure, the thermalinterface configured to mate with the conductor; the conductor comprisesa first mechanical connector; the thermal interface comprises a secondmechanical connector configured to mate with the first mechanicalconnector to attach the conductor to the battery enclosure; the firstmechanical connector comprises a male dovetail connector and the secondmechanical connector comprises a female dovetail connector configured toaccept the male dovetail connector to attach the conductor to thebattery enclosure; positioning a thermal window in the batteryenclosure, the thermal window configured to transfer thermal energy inand out of the battery enclosure; connecting a thermal substrate to thebattery enclosure in the thermal window, the thermal substrateconfigured to transfer thermal energy in and out of the batteryenclosure while providing a physical barrier into the battery enclosure;thermally connecting the thermoelectric device with the thermalsubstrate to thermally connect the thermoelectric device to the heatspreader; positioning the thermoelectric device outside of the batteryenclosure; connecting a blower and duct assembly to the batteryenclosure, the blower and duct assembly configured to push or pull airacross the waste side of the thermoelectric device, and furthercomprising connecting a blower in the blower and duct assembly, theblower configured to optimize system efficiency such that airflow isincreased or decreased to match heating or cooling requirements of thebattery cell; connecting a blower and duct assembly in thermalcommunication with the thermoelectric device and configured to push orpull air across the waste side of the thermoelectric device, and furthercomprising connecting a blower in the blower and duct assembly, theblower configured to optimize system efficiency such that airflow isincreased or decreased to match heating or cooling requirements of thebattery cell; the waste side of the thermoelectric device is in thermalcommunication with air via a waste heat exchanger; the waste side of thethermoelectric device comprises the waste heat exchanger; the heatspreader comprises a break in the pyrolytic graphite sheet, the breakconfigured to increase a travel path for electric current through theheat spreader to increase resistive heating capacity of the heatspreader; the pyrolytic graphite sheet is crinkled to increase a lengthof a surface of the pyrolytic graphite sheet, the increased length ofthe surface of the pyrolytic graphite sheet configured to increase atravel path for electric current through the pyrolytic graphite sheet toincrease resistive heating capacity of the heat spreader; the conductorextends substantially an entirety of a dimension of the heat spreader toprovide structural integrity to the heat spreader; the heat spreaderfurther comprises at least one other pyrolytic graphite sheet in thermaland electrical communication with the conductor, the at least one otherpyrolytic graphite sheet extending substantially in parallel with thepyrolytic graphite sheet; the conductor is in electrical communicationwith the at least one other pyrolytic graphite sheet to heat the batterycell upon application of electric current to the at least one otherpyrolytic graphite sheet via the conductor, the conductor in thermalcommunication with the at least one other pyrolytic graphite sheet totransfer thermal energy to and from the at least one other pyrolyticgraphite sheet; the heat spreader further comprises a thermal connectorbetween the pyrolytic graphite sheet and the at least one otherpyrolytic graphite sheet, the thermal connector configured to transferthermal energy between the pyrolytic graphite sheet and the at least oneother pyrolytic graphite sheet; the conductor comprises the thermalconnector; the thermal connector comprises a metallic materialconfigured to transfer electric current between the pyrolytic graphitesheet and the at least one other pyrolytic graphite sheet; thermallyconnecting the heat spreader to an other battery cell on a side of theheat spreader opposite a side of the heat spreader in thermallyconnected with the battery cell; the thermal connector is positionedbetween the sides of the heat spreader in thermal communication with thebattery cell and the other battery cell; the thermal connector is indirect thermal communication with the battery cell and the other batterycell to reduce thermal contact resistance associated with the heatspreader; the heat spreader further comprises a metallic substrate inthermal communication with the pyrolytic graphite sheet; the pyrolyticgraphite sheet is in thermal communication with the battery cell suchthat the pyrolytic graphite sheet functions as thermal interface betweenthe battery cell and the metallic substrate; the pyrolytic graphitesheet extends along a surface of the metallic substrate on at least twosides of the metallic substrate; the pyrolytic graphite sheet extends atleast half a cross-sectional perimeter of the metallic substrate; themain side of the thermoelectric device is positioned over at least aportion of the metallic substrate, and the pyrolytic graphite sheetextends to be between the main side of the thermoelectric device and themetallic substrate to provide a thermal interface between thethermoelectric device and the metallic substrate, the thermal interfaceconfigured to transfer thermal energy between the main side of thethermoelectric device and the metallic substrate; the battery cell isheated by the heat spreader transferring thermal energy to the batterycell when electric current is applied to metallic substrate via theconductor; and/or the battery is cooled by the heat spreadertransferring thermal energy away from the battery cell via the pyrolyticgraphite sheet and the conductor when electric current is applied to thethermoelectric device in the second polarity.

The foregoing is a summary and contains simplifications, generalization,and omissions of detail. Those skilled in the art will appreciate thatthe summary is illustrative only and is not intended to be in any waylimiting. Other aspects, features, and advantages of the devices and/orprocesses and/or other subject matter described herein will becomeapparent in the teachings set forth herein. The summary is provided tointroduce a selection of concepts in a simplified form that are furtherdescribed below in the Detailed Description. This summary is notintended to identify key features or essential features of any subjectmatter described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing is a summary and contains simplifications, generalization,and omissions of detail. Those skilled in the art will appreciate thatthe summary is illustrative only and is not intended to be in any waylimiting. Other aspects, features, and advantages of the devices and/orprocesses and/or other subject matter described herein will becomeapparent in the teachings set forth herein. The summary is provided tointroduce a selection of concepts in a simplified form that are furtherdescribed below in the Detailed Description. This summary is notintended to identify key features or essential features of any subjectmatter described herein.

FIG. 1 is a schematic illustration of an embodiment of an electricaldevice thermal management system.

FIG. 2 is a schematic illustration of an embodiment of some componentsof an electrical device thermal management system.

FIG. 3 is a schematic illustration of an embodiment of some componentsof an electrical device thermal management system.

FIG. 4 illustrates an embodiment of an electrical device thermalmanagement system for a battery.

FIG. 5 illustrates side and front views of an embodiment of a heatspreader.

FIG. 6 illustrates an embodiment of graphite sheets of a heat spreader.

FIG. 7 illustrates an embodiment of graphite sheets of a heat spreader.

FIG. 8 illustrates an embodiment of an isotropic structure of a metal.

FIG. 9 illustrates an embodiment of graphite sheets of a heat spreaderwith thermal/electrical connectors.

FIG. 10 illustrates an embodiment of a heat spreader.

FIG. 11 illustrates an embodiment of a heat spreader.

FIG. 12 illustrates an embodiment of a heat spreader.

FIG. 13 illustrates an embodiment of a heat spreader.

FIG. 14 illustrates an embodiment of a graphite sheet of a heatspreader.

FIG. 15 illustrates an embodiment of a graphite sheet of a heatspreader.

FIG. 16 illustrates an embodiment of a graphite sheet of a heatspreader.

FIG. 17 illustrates an embodiment of a heat spreader with athermal/electrical substrate.

FIG. 18 illustrates an embodiment of a stack of battery cells and heatspreaders.

FIG. 19 illustrates an embodiment of a battery case with a thermalinterface and a thermal window.

FIG. 20 illustrates an embodiment of a battery case with a thermalinterface and a thermal window.

FIG. 21 illustrates an embodiment of a battery case with a thermalinterface and a thermal window.

FIG. 22 illustrates an embodiment of a battery case with a thermalinterface and a thermal window.

FIG. 23 illustrates an embodiment of an air duct and blower system orassembly.

FIG. 24 illustrates an embodiment of an air duct and blower system orassembly.

FIG. 25 illustrates an embodiment of an air duct and blower system orassembly.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. The illustrative embodiments described in thedetailed description and drawings are not meant to be limiting. Otherembodiments may be utilized, and other changes may be made, withoutdeparting from the spirit or scope of the subject matter presented here.It will be readily understood that the aspects of the presentdisclosure, as generally described herein, and illustrated in thefigures, may be arranged, substituted, combined, and designed in a widevariety of different configurations, all of which are explicitlycontemplated and made a part of this disclosure.

In particular, embodiments disclosed herein pertain to thermalmanagement (e.g., heating and/or cooling) of electrical devicesincluding but not limited to batteries with or without thermoelectricsystems.

Thermoelectric (TE) systems can be operated in either heating/cooling orpower generation modes. In the former, electric current is passedthrough a TE device to pump the heat from the cold side to the hot sideor vice versa. In the latter, a heat flux driven by a temperaturegradient across a TE device is converted into electricity. In bothmodalities, the performance of the TE device is largely determined bythe figure of merit of the TE material and by the parasitic(dissipative) losses throughout the system. Working elements in the TEdevice are typically p-type and n-type semiconducting materials.

A thermoelectric system or device as described herein can be athermoelectric generator (TEG) which uses the temperature differencebetween two fluids, two solids (e.g., rods), or a solid and a fluid toproduce electrical power via thermoelectric materials. Alternatively, athermoelectric system or device as described herein can be a heater,cooler, or both which serves as a solid state heat pump used to moveheat from one surface to another, thereby creating a temperaturedifference between the two surfaces via the thermoelectric materials.Each of the surfaces can be in thermal communication with or comprise asolid, a liquid, a gas, or a combination of two or more of a solid, aliquid, and a gas, and the two surfaces can both be in thermalcommunication with a solid, both be in thermal communication with aliquid, both be in thermal communication with a gas, or one can be inthermal communication with a material selected from a solid, a liquid,and a gas, and the other can be in thermal communication with a materialselected from the other two of a solid, a liquid, and a gas.

The thermoelectric system can include a single thermoelectric device(TED) or a group of thermoelectric devices (TEDs) depending on usage,power output, heating/cooling capacity, coefficient of performance (COP)or voltage. Although the examples described herein may be described inconnection with a heating/cooling system, the described features can beutilized with either a power generator or a heating/cooling system.

The term “thermal communication” is used herein in its broad andordinary sense, describing two or more components that are configured toallow heat or thermal energy transfer from one component to another(e.g., between components) that performs a desired function or achievesa desired result. For example, such thermal communication can beachieved, without loss of generality, by snug contact between surfacesat an interface; one or more heat transfer materials or devices betweensurfaces; a connection between solid surfaces using a thermallyconductive material system, wherein such a system can include pads,thermal grease, paste, one or more working fluids, or other structureswith high thermal conductivity between the surfaces (e.g., heatexchangers); other suitable structures; or combinations of structures.Substantial thermal communication can take place between surfaces thatare directly connected (e.g., contact each other to provide directthermal communication, but may include, for example, thermal grease orthe like) or indirectly connected via one or more interface materials.“Thermal communication” does not include incidental heat (e.g., thermalenergy) transfer between two or more separate components unless heattransfer between the two or more components occurs via one or moreworking fluids configured to flow when heat transfer is needed (e.g., aworking fluid circulated between the two or more components) and/or heatpipe. “Thermal communication” does not include possible heat transferbetween two or more components that are separated by a fluid that is notcirculated between the two or more components, such as for example, airthat is not moved by, for example, a blower relative to the two or morecomponents.

As used herein, the terms “shunt,” “cold plate,” “heat spreader,”“heat/hot plate,” “fin,” and “heat exchanger” have their broadestreasonable interpretation, including but not limited to a component(e.g., a thermally conductive device or material) that allows heat orthermal energy to flow from one portion of the component to anotherportion of the component. In some embodiments, heat spreader can be aheat exchanger that functions as a cold plate, heat/hot plate, and/orfin depending on the disclosed functionality. Shunts can be in thermalcommunication with one or more thermoelectric materials (e.g., one ormore thermoelectric elements) and in thermal communication with one ormore heat exchangers of the thermoelectric assembly or system. Shuntsdescribed herein can also be electrically conductive and in electricalcommunication with the one or more thermoelectric materials so as toalso allow electrical current to flow from one portion of the shunt toanother portion of the shunt (e.g., thereby providing electricalcommunication between multiple thermoelectric materials or elements).Heat exchangers (e.g., heat spreaders, tubes, and/or conduits) can be inthermal communication with the one or more shunts, one or more TEDs,and/or one or more working fluids of the thermoelectric assembly orsystem. Various configurations of one or more shunts and one or moreheat exchangers can be used (e.g., one or more shunts and one or moreheat exchangers can be portions of the same unitary element, one or moreshunts can be in electrical communication with one or more heatexchangers, one or more shunts can be electrically isolated from one ormore heat exchangers, one or more shunts can be in direct thermalcommunication with the thermoelectric elements, one or more shunts canbe in direct thermal communication with the one or more heat exchangers,an intervening material can be positioned between the one or more shuntsand the one or more heat exchangers). Furthermore, as used herein, thewords “cold,” “hot,” “cooler,” “hotter,” “coldest,” “hottest,” and thelike are relative terms, and do not signify a particular temperature ortemperature range.

Embodiments disclosed herein include systems and methods capable ofthermally managing an electrical device (e.g., battery) by applyingdirect or indirect thermoelectric (TE) cooling and/or heating to theelectrical devices. Such devices can often benefit from thermalmanagement. Some embodiments will be described with reference toparticular electrical devices, such as, for example, batteries, batterycasings and battery cells. However, at least some embodiments disclosedherein are capable of providing thermal management to other electricaldevices, such as, for example, insulated-gate bipolar transistors(IGBTs), other electrical devices, or a combination of devices. At leastsome such devices can suffer from operation outside of a preferredtemperature range. The operation of some embodiments is described withreference to a cooling mode of operation. However, some or all of theembodiments disclosed herein can have a heating mode of operation, aswell. In some situations a heating mode of operation can be employed tomaintain the temperature of an electrical device above a thresholdtemperature, under which the electrical device may degrade or exhibitimpaired operation. TE devices are uniquely suited to provide bothheating and cooling functions with minimum complications for systemarchitecture.

Battery thermal management is desired to maintain vehicle batterieswithin an optimum temperature range. This maximizes both performance anduseful life of the battery. Although the examples described herein maybe described in connection with a heating/cooling system for a battery,the described features can be utilized with other electrical devices asdescribed herein.

In general, for most battery chemistries, as temperatures rise,discharge time (capacity) increases, ability to deliver currentincreases and charging time decreases. For these metrics, high batterytemperatures are generally favorable. However, for the metric of batterylife, the opposite is generally true. High temperatures reduce usefulbattery life. It has been found that maintaining batteries within anideal temperature range or prescribed temperature at the right time canbalance battery life with other performance metrics.

Start-stop batteries may be located under the hood of a vehicle. Thetemperature under the hood of a vehicle is typically above the ideal orprescribed temperature range. To improve the useful life of the batteryit is best to maintain the battery at lower temperatures than the underhood environment of a vehicle.

Different thermal management strategies have been devised for batteries,but thermoelectric thermal management can be beneficial over otherthermal management strategies for many reasons. One advantage of TEthermal management is it places little or no other (e.g., additional)burden on the vehicle in terms of coolant hoses or refrigerant lines.Another advantage is electric power for the TE thermal management can bedelivered by the battery itself making the system “stand-alone” or“in-line”.

For lithium-ion start-stop batteries, rapid heating prior to enginestart-up is generally helpful in boosting the current delivering abilityof the battery cells. If this ability (e.g., rapid heating prior toengine start-up) is increased, the battery pack can be made smaller(e.g., less total amount of battery cells) at reduced cost and improveperformance relative to competing products like lead acid batteries. Tomake the heating system practical, the heat must be delivered to thebatteries at a high rate (e.g., heat flux) requiring a high powerheating system.

There are a variety of ways in which TE devices can be used forelectrical device cooling and/or heating tasks. As described herein, TEdevices can include one or more TE elements, TE assemblies and/or TEmodules. In some embodiments, a TE system can include a TE device, whichcomprises a first side and a second side opposite the first side. Insome embodiments, the first side and second side can be a main surfaceand waste surface, or heating surface and cooling surface (or a mainside and waste side, or heating side and cooling side). In certainembodiments, the main surface can control the temperature of a deviceunder thermal management while the waste surface connects is connectedto a heat source or heat sink. A TE device can be operably coupled witha power source. The power source can be configured to apply a voltage tothe TE device. When voltage is applied in one direction, one side (e.g.,the first side) creates heat while the other side (e.g., the secondside) absorbs heat. Switching polarity of the circuit creates theopposite effect. In a typical arrangement, a TE device comprises aclosed circuit that includes dissimilar materials. As a DC voltage isapplied to the closed circuit, a temperature difference is produced atthe junction of the dissimilar materials. Depending on the direction ofthe electric current, heat is either emitted or absorbed at a particularjunction. In some embodiments, the TE device includes several solidstate P- and N-type semi-conductor elements connected in series; orgroups (e.g., modules) of P- and N-type semi-conductor elementsconnected in series, with the groups connected in a parallel and/orseries configuration to provide operational robustness to the TE device.

In certain embodiments, the junctions are sandwiched between twoelectrical isolation members (e.g., ceramic plates), which can form thecold side and the hot side of the TE device. The cold side can bethermally coupled (directly or indirectly) to an object (e.g.,electrical conductor, electrical device under thermal management,battery cell, heat spreader/fin, etc.) to be cooled and the hot side canbe thermally coupled (directly or indirectly) to a waste heat removalsystem which dissipates heat to the environment. Any suitable techniquecan be used including, but not limited to a heat exchanger, heat sink,heat pipe and/or exposure to ambient air. In some embodiments, the hotside can be thermally coupled (directly or indirectly) to an object(e.g., electrical conductor, electrical device under thermal management,battery cell, heat spreader/fin, etc.) to be heated. Certainnon-limiting embodiments are described below.

In some embodiments, a heat pipe can be provided as a waste heat removalor transport mechanism. Waste heat from a TE device can be dissipated ina heat sink. Examples of heat sinks include heat exchangers, wastestreams, other structures for dissipating heat such as a battery case asdiscussed herein, and combinations of structures. A heat sink can beattached (directly or indirectly) to the waste side or surface of the TEdevice. The heat sink can be cooled by air, liquid, or, alternatively,it can be a solid member connecting the TE device with a bigger solidheat sink such as a battery case, car frame, or another structuralelement that dissipates heat effectively. However, in practicalapplications, such as, for example, a battery thermal management system,there can be packaging constraints that limit the possibility ofbringing the cooling media close to the waste side of the TE device.Alternatively, a heat or thermal transport device may be used to movethe heat from the waste side of the TE device to another location whereheat dissipation may be implemented effectively.

In some embodiments, a heat transfer device or exchanger can be used toconnect the waste side or surface of the TE device to a heat sink wherethe heat is ultimately dumped by, for example, air, liquid, or solid.Such a heat sink can be for example the liquid cooling circuit of thecar, a radiator or an air cooled heat sink, ambient air, working fluid,fluid reservoir, or a solid body (e.g., battery case or car frame).

Electrical Device Thermal Management Systems

Electrical device thermal management systems, and in particular, batterythermal management systems (BTMS), can be used to control temperaturesand monitor conditions of batteries and arrays of batteries to preventbattery failure and/or safety related failure. A BTMS can improve theoverall conditions of battery operation by both managing the thermalenvironment and also being sufficiently reliable so that overall systemperformance is not degraded.

A variety of embodiments of battery thermal management systems arediscussed herein to illustrate various configurations. The particularembodiments and examples are only illustrative and features described inone embodiment or example may be combined with other features describedin other embodiments or examples. Accordingly, the particularembodiments and examples are not intended to be restrictive in any way.

In some embodiments, a BTMS includes at least one battery, battery case,battery cell, plate (e.g., heat spreader 28 as discussed herein) incontact with the cell, electrode, and/or battery array. In certainembodiments, a battery thermal management system can be used to bothheat and cool batteries, battery cells, and/or battery arrays. Forexample, the battery thermal management system can be integrated withthe at least one battery, the battery thermal management system can beintegrated with an enclosure wherein the at least one battery or batterycell is contained, or the thermal management system can be positioned inthermal communication with the at least one battery or battery cell.

FIG. 1 is a schematic illustration of an embodiment of an electricaldevice thermal management system or battery thermal management system(BTMS) 10. As illustrated in FIG. 1, the BTMS 10 can include one or morebattery cell(s) 12 of a battery 14. The battery cell(s) 12 include oneor more electrodes 18. In some embodiments, the battery cell(s) 12 isenclosed by or housed in a battery case, casing, or enclosure 16 (or anelectrical device enclosure). The BTMS 10 can further include one ormore TEDs 20 each having a first side 22 (e.g., a main surface forproviding heating or cooling to the battery cell(s) 12 via, for example,direct thermal communication or a main side heat exchanger) and a secondside 24 (e.g., a waste surface for transferring thermal energy to oraway from the TED 20 via, for example, direct thermal communication or awaste side heat exchanger). In some embodiments, the first side 22 is inthermal communication with a portion (e.g., a fin 26) of a heatspreader/plate 28.

The heat spreader 28 includes a contact portion 30 in thermalcommunication with a portion of the battery cell(s) 12. The contactportion 30 can include the heat spreader 28 being in thermalcommunication with a temperature sensitive region of the electricaldevice (e.g., battery cell(s) 12). The temperature sensitive region ofthe electrical device can be, for example, a hotspot when the electricaldevice is operating. For example, when a battery 14 is charging ordischarging, the battery cell(s) 12 may have hotspots (e.g., one or moreregions that have a higher temperature relative to other regions of thebattery cell(s) 12). Accordingly, the contact portion 30 of the heatspreader 28 may include at least being over and in thermal communicationwith the hotspot to thermally manage the battery cell(s) 12 as discussedherein.

The fin 26 can extend in the same direction, perpendicular to, or atvarious other angles relative to the cell contact portion 30. In someembodiments, the second side 24 of the TED 20 is coupled or configuredto be coupled to a heat source and/or heat sink system 32 or thermalenergy transfer system (e.g., for providing heat to the TE device 20 orfor dissipation or removal of heat from the TE device 20).

In some embodiments, the battery case 16, second side 24 (e.g., wastesurface) of the TED 20, heat source and/or heat sink system 32, and/orbattery cell(s) 12 are exposed to the ambient air such that heat can bedissipated or removed accordingly to the environment (e.g., an air duct90 and blower 92 system, as discussed herein, and in particular inreference to FIGS. 23-25). In some embodiments, the battery case 16 issealed and TED 20 is positioned within the battery case 16 such that theTED 20 is in thermal communication with the battery case 16 that canfunction as the heat sink or heat source).

In some embodiments, a thermoelectric (TE) thermal management system 34is provided comprising one or more TEDs 20 in thermal communication withcomponents of the electrical device and/or heat spreaders 28. The TEthermal management system 34 controls the TED 20 to heat or cool thebattery cells 12 as discussed herein. A controller of the TE thermalmanagement system 34 may be separate or integrated with a controller 36as discussed herein.

In some embodiments, the BTMS 10 includes a power source 38 forproviding electrical current to the heat spreaders 28 and/or TED 20and/or as discussed herein. In other embodiments, the heat spreaders 28and/or TEDs are powered in-line with the battery 14. In someembodiments, the BTMS 10 includes a controller 36 and/or printed circuitboard or substrate 79 (see for example FIG. 18) in electricalcommunication with the various components of the BTMS 10, including thebattery cell 12, battery 14, battery case 16, heat spreader 28, TED 20,heat source and/or heat sink system 32, TE thermal management system 34,power source 38, and/or sensor 40. The controller 36 can be integratedonto a printed circuit board 79 (see for example FIG. 18) having one ormore controllers as discussed herein. The controller 36 can include athermal management controller that can operate in a heating mode orcooling mode to heat or cool, respectively, an electrical device (e.g.,battery cell(s) 12). The printed circuit board 79 can be positionedwithin the battery case 16 and can include a power connection forsupplying electric power to the TE thermal management system 34 or othersystems discussed herein requiring electrical power.

In some embodiments, the BTMS 10 includes one or more sensors 40 (e.g.,electrical, temperature) for providing electrical and/or temperatureinformation of the battery cells 12, TED 20, ambient temperature, and/ortemperature within the battery case 16 to the controller 36 such thatthe electrical power (e.g., current, voltage) to the TED 20 can beadjusted accordingly to provide the appropriate level of heating orcooling as desired or required to maintain the temperature of thebattery at an optimum level.

As discussed herein, thermally managing battery cells can include usingone or more thermoelectric devices (TEDs) or modules. In someembodiments, one or more TEDs may be used to cool or heat one or morebattery cases, battery cells, heat spreaders, cold plates, heat/hotplates, and/or fins in contact with the battery cells, air circulatingwithin, about, and/or blown through the battery case, electrodes of thebatteries, battery terminals, and/or other components. As discussedherein, thermally managing battery cells can include using one or moreheat spreaders to heat or cool (with or without TEDs) one or morebattery cases, battery cells, air circulating within, about, and/orblown through the battery case, electrodes of the batteries, batteryterminals, and/or other components.

Generally, in order to use TEDs efficiently, thermal losses (e.g.,thermal resistance) should be reduced along the thermal path from theheat source to the TED. Therefore, the location (e.g., position,alignment) of the one or more TEDs needs to be optimized based on thespecifics of the electrical device (e.g., battery cell construction) andlocalization of heat production.

As discussed herein, for thermal management of start-stop batteries itcan be advantageous to use a TE thermal management system. However,typically a TE thermal management system sized for sufficient cooling ofthe battery would not provide enough thermal capacity for a high powerheating requirement. Resistive heating elements may be much moresuitable for a high power heating application. For many reasonsincluding cost, performance, and efficiency, in some embodiments, it canbe beneficial to combine the TE thermal management system (e.g., coolingand/or heating system) with a high power heating system (e.g.,resistive, Joule heating). However, in some embodiments, a high powerheating system is provided for thermal management of an electricaldevice without or not in combination with a TE thermal managementsystem.

In some embodiments, Pyrolytic graphite (carbon) is provided as themedium or interface material for combining the two thermal managementsolutions. Pyrolytic graphite is both electrically resistive and highlythermally conductive. The resistive property makes it useful as a thinresistive heating element that can be placed between battery cells forhigh power heating applications or systems. The thermally conductiveproperty is useful for transferring heat to and from battery cellsand/or to and from a thermoelectric cooling module.

Pyrolytic graphite has many unique properties. One such property is itsin-plane (e.g., plane 63 as discussed herein, see for example FIG. 12)thermal conductivity which can be up to 1700 W/m*K. As a comparison,copper and aluminum have thermal conductivities of about 400 W/m*K and205 W/m*k, respectively. The higher the thermal conductivity of amaterial, the lower the temperature gradient will be through thematerial. This can be beneficial to certain thermoelectric temperaturemanagement systems because the efficiency of these devices is improvedgreatly by reducing the temperature difference between the item ordevice to be thermally managed and the ambient thermal reservoirtemperature.

FIG. 2 is a schematic illustration of an embodiment of some componentsof an electrical device thermal management system. As illustrated inFIG. 2, Pyrolytic graphite sheets, layers, or surfaces 42 forming atleast a part of a heat spreader 28 as discussed herein can be connected,attached, or coupled to the electrical component(s) (e.g., batterycell(s) 12, battery 14) such that they are in thermal and/or electricalcommunication in any suitable manner (e.g., adhesive, directly,indirectly via interstitial materials (grease) or other interfaces,press-fit, screws, nuts, bolts, nails). In some embodiments, tightcontact pressure is maintained in any suitable manner between surfacesof the graphite sheet 42 and the electrical component(s) (e.g., batterycell(s) 12, battery 14) to maintain contact (e.g., direct thermal and/orelectrical communication). In some embodiments, surfaces of theelectrical component(s) (e.g., battery cell(s) 12, battery 14) conformto the surfaces of the graphite sheet 42 and/or vice versa via suchcontact pressure or attachment.

As illustrated in FIG. 2, one or more thermal/electrical connectors orelevators 44 forming at least a part of a heat spreader 28 as discussedherein can be connected, attached, or coupled to the electricalcomponent(s) (e.g., battery cell(s) 12, battery 14) such that they arein thermal and/or electrical communication in any suitable manner (e.g.,adhesive, directly, indirectly via interstitial materials (grease) orother interfaces, press-fit, screws, nuts, bolts, nails). Thethermal/electrical connector 44 can be connected, attached, or coupledto the graphite sheet 42 such that they are in thermal and/or electricalcommunication in any suitable manner (e.g., over molded, adhesive,directly, indirectly via interstitial materials (grease) or otherinterfaces, press-fit, screws, nuts, bolts, nails). In some embodiments,surfaces of the electrical component(s) (e.g., battery cell(s) 12,battery 14) conform to the surfaces of the thermal/electrical connector44 and/or vice versa via such contact pressure or attachment. In someembodiments, surfaces of the graphite sheet 42 conform to the surfacesof the thermal/electrical connector 44 and/or vice versa via suchcontact pressure or attachment. Accordingly, as illustrated in FIG. 2,the electrical component(s) (e.g., battery cell(s) 12, battery 14),graphite sheet 42, and thermal/electrical connector 44 can be can beconnected, attached, or coupled to each other such that they are inthermal and/or electrical communication with each other.

FIG. 3 is a schematic illustration of an embodiment of some componentsof an electrical device thermal management system. As illustrated inFIG. 3, an electrical connection 46 is coupled to a graphite sheet 42 toprovide resistive heating to the graphite sheet 42 via a power source38. In some embodiments, the electrical connection or junction 46 iscoupled to the battery cell(s) 12 to provide the power source. Theelectrical connection 46 can be coupled to the graphite sheet 42 in anysuitable manner (e.g., mechanical coupling, adhesive).

As illustrated in FIG. 3, a mechanical, thermal and/or electricalconnection 48 (e.g., conductor) connects the graphite sheet 42 and/orthermal/electrical connector 44 to the battery case 16, TED 20, and/orheat source/heat sink system 32. The connection 48 can connect, attach,or couple the graphite sheet 42 and/or thermal/electrical connector 44to the TED 20 to physically fix the TE thermal management system 34(e.g., TED 20) relative to the graphite sheet 42 and/orthermal/electrical connector 44 as well as provide thermal communicationbetween the respective components in any suitable manner (e.g.,adhesive, directly, indirectly via interstitial materials (grease) orother interfaces, press-fit, screws, nuts, bolts, nails). The connection48 can connect, attach, or couple the graphite sheet 42 and/orthermal/electrical connector 44 to the battery case 16 to physically fixthe graphite sheet 42 and/or thermal/electrical connector 44 relative tothe battery case 16 as well as provide thermal and/or electricalcommunication between the respective components in any suitable manner(e.g., adhesive, directly, indirectly via interstitial materials(grease) or other interfaces, press-fit, screws, nuts, bolts, nails).The connection 48 can connect, attach, or couple the graphite sheet 42and/or thermal/electrical connector 44 to the heat source and/or heatsink system 32 to physically fix the graphite sheet 42 and/orthermal/electrical connector 44 relative to the heat source and/or heatsink system 32 as well as provide thermal and/or electricalcommunication between the respective components in any suitable manner(e.g., adhesive, directly, indirectly via interstitial materials(grease) or other interfaces, press-fit, screws, nuts, bolts, nails).

FIG. 4 illustrates an embodiment of an electrical device thermalmanagement system for a battery 14. In some embodiments, as illustratedin FIG. 4, a battery 14 having a BTMS 10 can have battery cells 12stacked against each other (e.g., facing each other on certain surfacesof the battery cells 12). Heat spreaders 28 can be positioned betweenthe battery cells 12. The heat spreaders 28 can be in thermalcommunication with the battery cells via contact portion(s) 30 inthermal communication with the battery cells 12 in any suitable manneras discussed herein.

As illustrated in FIG. 4, the heat spreaders 28 can have a fin 26 thatprojects beyond a periphery or boundary of the battery cells 12 into ortoward the battery case 16. The fin 26 can be an extension of the heatspreader 28 composed of substantially the same material as the heatspreader 28. In some embodiments, the fin 26 can be attached to the heatspreader and made of different material from the heat spreader 28 (e.g.,a heat spreader 28 can be graphite while the fin 26 may be metallic).

A TED 20 of a TE thermal management system 34 may be positioned on thefin 26 to be in thermal communication with the heat spreader 28 via thefin 26. The TED 20 can be in thermal communication with the fin 26 inany suitable manner as discussed herein (e.g., via a direct thermalcommunication or via an interstitial material). In some embodiments, thefin 26 can be a feature of the heat spreader 28 that tapers or reducesto a smaller surface area and/or volume to concentrate thermal energytransfer to a connection 48 and/or TED 20. In some embodiments, the fin26 is an extension of the heat spreader 28 beyond a perimeter of, forexample, a battery cell 12 with similar dimensions as the heat spreader28 portions in thermal communication with the battery cell 12.

The main side or surface 22 of the TED 20 can be in thermalcommunication with the fin 26. The waste side or surface 24 of the TED20 can be in thermal communication with a heat source and/or heat sink32. As illustrated in FIG. 4, a heat source and/or heat sink system 32 amay be in thermal communication (e.g., direct/substantial thermalcommunication) with the battery case 16. In some embodiments, thebattery case 16 may function as the heat source and/or heat sink. Asalso illustrated and FIG. 4, the heat source and/or heat sink system 32b may not be in direct thermal communication with the battery case 16,the heat source and/or heat sink system may provide or remove thermalenergy via any suitable means such as thermal energy transfer via aworking fluid to a heat source (e.g., an engine coolant circuit) and/ora heat sink (e.g., a radiator) within or outside the battery 14.

Embodiments of Heat Spreaders

FIG. 5 illustrates side and front views of an embodiment of a heatspreader 28. As discussed herein, a combined pyrolytic graphiteresistive heater and heat sink 28 (or heat spreader) is providedcomprising one or more pyrolytic graphite sheets, layers, or surfaces 42positioned between electrical components (e.g., battery cells 12) of theelectrical device (e.g., battery 14) as discussed herein. The heatspreader 28 can have a voltage spreader 50 (e.g., conductor) or otherpower source to supply electrical power (e.g., current, voltage) to thePyrolytic graphite sheets 42. When electrical power is supplied to thepyrolytic graphite sheets 42, the heat spreader 28 can function as aresistive heater. For example, as electrical current passes through thegraphite sheets 42 from a positive end to a negative end of the voltagespreader 50, the electrical current heats up the graphite sheets 42 dueto the electrical resistance of the graphite sheets 42. In someembodiments, the voltage spreader 50 can include or be composed ofthermal/electrical connectors 44 as discussed herein.

As illustrated in FIG. 5, a TE thermal management system 34 is providedcomprising one or more TEDs 20 in thermal communication with componentsof the electrical device and/or pyrolytic graphite sheets 42. The TEDs20 can be positioned on and in thermal communication with the heatspreader 28 via a fin 26 as discussed herein. In some embodiments, acombined pyrolytic graphite resistive heater and heat sink is providedwithout a TE thermal management system 34 (e.g., a TED 20). In someembodiments, a resistive heater is provided with a voltage spreader 50to provide electrical power to the graphite sheets 42 without a TEthermal management system 34 and/or TED 20.

FIGS. 6 and 7 illustrate an embodiment of graphite sheets 42 of a heatspreader 28. As illustrated in FIGS. 6 and 7, the layered structure ofpyrolytic graphite (e.g., sheets 42 as discussed herein) is responsiblefor its anisotropic thermal conductivity. Covalent bonds 49 withinlayers of carbon atoms are responsible for high thermal conductivitywithin the plane and relatively weak bonds 51 between layers of carbonatoms reduces thermal and electrical conductivity normal to the plane.For a combined heating and cooling solution the heat transfer orthogonalto the planes is generally less important due to distances of which heatis to be transferred. For example, orthogonal to the plane, thethickness of the graphite portion (e.g., sheet, surface) may be as smallas 25 μm but within plane, heat transfer may take place over hundreds ofmillimeters.

Although heat and electrical transfer orthogonal to the plane isgenerally less of a concern, this transfer can be improved by usingthermal/electrical “elevators” or “conveyer belts” (e.g.,thermal/electrical connectors 44) to deliver heat or electrons to thevarious layers of graphite (e.g., forming a graphite metal composite).In contrast to the anisotropic properties of the graphite, metals haveisotropic thermal and electrical properties. For example, the isotropicstructure of a metal, such as copper 52, is illustrated in FIG. 8.Certain metals (e.g., copper, aluminum) therefore make good “elevators”to transfer heat and electrons between graphite layers as illustrated inFIG. 9.

FIG. 9 illustrates an embodiment of graphite sheets 42 of a heatspreader 28 with thermal/electrical connectors 44. Thethermal/electrical connectors 44 can be formed within various layers ofgraphite sheets 42. The thermal/electrical connectors 44 can transferheat or electrons to the different layers of graphite sheets 42 in anorthogonal or normal direction 54 relative to the graphite sheets 42(e.g., orthogonal to a plane 63 extending substantially along or inparallel to the graphite sheets 42, see for example FIG. 12). Thethermal/electrical connectors 44 can thereafter transfer heat orelectrons into the different layers of graphite sheets 42 in a paralleldirection 56 into the graphite sheets 42 (e.g., along a plane 63extending substantially in parallel to the graphite sheets 42).Accordingly, the thermal/electrical connectors 44 provide thermal andelectrical communication between the layers of graphite sheets 42 thatotherwise would be substantially inhibited or mitigated.

The surfaces of the thermal/electrical connectors 44 may also improvethe thermal contact resistance (e.g., decrease thermal contactresistivity and/or increase thermal contact conductivity) between thegraphite sheets 42 and the electrical components (e.g., battery cells12) or between the graphite sheets 42 and the TED 20 over just usinggraphite alone for the thermal interface. This may be due to potentiallybetter surface characteristics of the thermal/electrical connectors 44contact surface that can further improve the performance of the BTMS 10.

In some embodiments, the materials used as thermal/electrical connectors44 is injected (e.g., injection aluminum molding) or press fit intospaces, apertures or holes formed in the graphite sheets or surfaces 42.In some embodiments, the surface of the graphite sheets 42 is doped withsuch metals. In some embodiments, the surface of the graphite sheets 42is cast with certain metals (e.g., having a disk-shaped or othershapes). In some embodiments, the graphite sheet 42 is over-molded withthe thermal/electrical connectors or elevators 44 or vice versa asillustrated in FIGS. 10-12. The elevators 44 can be of any suitableshape or size and can be coupled or integrated into the graphite surface42 in any suitable manner.

FIGS. 10-12 illustrate an embodiment of a heat spreader 28. In someembodiments, an electrical connection 46 is coupled to the heat spreader28 as discussed herein to provide resistive heating to or of thegraphite sheets 42 via a voltage spreader 50 or other power source. Theelectrical connection 46 can be coupled to the graphite sheet 42 and/orvoltage spreader 50 in any suitable manner (e.g., mechanical coupling,adhesive) as discussed herein. Further, the voltage spreader 50 can becoupled to the graphite sheet 42 in any suitable manner as discussedherein.

In some embodiments, a mechanical, thermal, and/or electrical connection48 is over molded over a portion of the graphite sheet 42. Theconnection 48 can be a multi-function connection as discussed herein andcomposed of, for example, metal as discussed herein. In someembodiments, the connection 48 can have a tapered dovetailed shape 58.The dovetail 58 can be shaped to connect, couple, mate, and/or attach toa corresponding component of the battery case 16 (e.g., thermalinterface 82 as discussed herein, and in particular in reference toFIGS. 19-21).

As illustrated in FIGS. 10-12, the dovetail 58 can be a male component(e.g., first mechanical connector). The battery case 16 can have acorresponding female component (e.g., second mechanical connector) toengage or accept the dovetail shape 58 in any suitable manner asdiscussed herein (e.g., interference fit as well as thermal grease). Theconnection 48 can physically secure or fix the heat spreader 28 relativeto the battery case 16. The dovetail 58 can provide at least a part ofthe mechanical, thermal, and/or electrical functionality to theconnection 48 as discussed herein.

As illustrated in FIGS. 11 and 12, the heat spreader 28 can have holesor openings 60. The openings 60 can extend through two or more layers ofgraphite sheets 42 (e.g. orthogonal to the graphite sheets or plainextending along or parallel to the graphite sheets 42). As illustratedin FIG. 11, the openings 60 can be near or at the periphery, boundary,or edge of the heat spreader 28. The connection 48 can be over moldedonto the openings 60 to provide the elevators 44 between the graphitesheets 42 as discussed herein. Accordingly, the connection 48 caninclude the elevators 44 at the boundaries, sides, or edges of the heatspreader 28. As illustrated in FIG. 12, the openings 60 can be includedthroughout an extent or surface area of the heat spreader 28, includingthe contact portion 30. The thermal elevators 44 can be provided or overmolded as discussed herein in the openings 60. Accordingly, the openings60 can be locations of thermal elevators 44 as desired throughout theheat spreader 28.

Accordingly, the connection 48, including the dovetail 58, can be overmolded over a portion of the heat spreader 28 to createthermal/electrical elevators 44 in the heat spreader 28. In someembodiments, the graphite sheets 42 are die-cut in irregular shapes toincrease contact area of the connection 48 between the graphite sheetsand, for example, the elevators 44 and/or voltage spreader 50.

As illustrated in FIGS. 11 and 12, the over molded components (e.g.including connection 48) can be provided on multiple edges or sides ofthe heat spreader 28. For example, as illustrated in FIG. 11, the overmolded components can be provided on opposite sides of the heat spreader28.

With continued reference to FIG. 11, a component 61 (e.g., conductor)that is, for example, over molded as discussed herein connection 43 canbe provided on an opposite side of the connection 48. The component 61can have thermal elevators 44 as discussed herein. While the component61 in some embodiments is not connected to, for example, the batterycase 16, the component 61 can provide the functionality of elevators 44as discussed herein as well as further structural integrity to the heatspreader 28. For example, the component 61 (as well as the over moldedconnection 48 on the opposite side of the heat spreader), can providestructural rigidity and strength to the graphite sheets 42.

As illustrated in FIG. 11, the over molded components (includingconnection 48 and component 61) can extend substantially an entirety ofa dimension (e.g., width, length) of the heat spreader 28 to providestructural integrity to the heat spreader 28 at least in part due to theover molded components being made of a more rigid material such asmetal. In some embodiments, the over molded components may extend lessthan (e.g., half or three-quarters) of a dimension of the heat spreader28 while providing structural integrity to the heat spreader 28.

As illustrated in FIG. 12, the openings 60 can be positioned throughoutthe heat spreader 28. For example, the openings 60 can be provided inthe heat spreader 28 in any desired pattern in any desired quantityextending along the plane 63 substantially parallel to the graphitesheets 42. The elevators 44 can be over molded onto and/or into the heatspreader 28 to provide the functionality of the elevators 44 asdiscussed herein throughout the plane 63 along the graphite sheets 42,including contact portion(s) 30.

FIG. 13 illustrates an embodiment of a heat spreader 28. The heatspreader 28 can be connected to a voltage source 62 (e.g., conductor) inany suitable manner as discussed herein, including thermal/electricalelevators 44. The voltage source 62 can drive an electric currentthrough the graphite sheets 42 of the heat spreader 28 as discussed herein to provide the functionality of a resistance heater to the heatspreader 28. To increase the effectiveness of the heat spreader 28functioning as a resistance heater, length of the conduction path of theelectric current through the graphite sheets 42 can be increased orlengthened (e.g. increase the resistance to electric current flowthrough the graphite sheets 42).

As illustrated in FIG. 13, that heat spreader 28 can have one or morecuts or breaks 64 provided in the heat spreader 28 along a plane 63parallel to the graphite sheets 42. The breaks 64 can be portions of theheat spreader 28 where the carbon atoms are not covalently bonded in thegraphite sheets 42 along the plane 63 parallel to the graphite sheets42. The breaks 64 can be provided in the heat spreader 28 duringmanufacture of the graphite sheets 42 and/or after the manufacturer ofthe graphite sheets 42, such as for example, by cutting or breaking thegraphite sheets (e.g., breaking covalent bonds) along, for example, thebreaks 64 illustrated in FIG. 13.

When an electric current is driven through the graphite sheets 42, theelectric current now not only has to travel or conduct from one end toanother end of the heat spreader 28, but the electric current also hasto travel or conduct along the serpentine path created in the graphitesheets from the positive terminal of the voltage source 62 to thenegative terminal of the voltage source 62. While a serpentine path fromone corner to an opposite corner of the heat spreader 28 is illustrated,any serpentine path through the heat spreader 28 can be provided. Or anyother pattern of breaks 64 can be provided in the heat spreader 28 toincrease the path length of the electric current flow through the heatspreader 28.

As illustrated in FIG. 13, the connection 48 and component 61 can beincluded as discussed herein while providing the serpentine path forcurrent flow. In order to direct the electric current to flow along theserpentine path and not throughout the connection 48 and component 61(e.g., as discussed herein for a voltage spreader 50 illustrated in FIG.5) electrical insulation 66 can be provided along portions of theconnection 48 and component 61 where electric current flow is notdesired. Electrical insulation 66 may still allow for thermalcommunication (e.g., transfer of thermal energy) as desired between BTMS10 components.

FIGS. 14-16 illustrate embodiments of graphite sheets 42 of a heatspreader 28. As another way to increase the path length of electriccurrent flow through the graphite sheets 42, the graphite sheets 42within a heat spreader 28 can be “crinkled” as illustrated in FIGS.14-16. For example, the graphite sheets may have bends, angles,curvatures, and/or zigzags along the plane 63 substantially parallel tothe heat spreader 28 as discussed herein. The overall longer length ofthe graphite sheets 42 themselves relative to a substantially samedimension of the heat spreader 28 increases the path or travel lengthfor the electric current flow to increase resistance heating asdiscussed herein. The crinkled heat spreaders 28 may incorporateelevators 44 as discussed herein. The dimensions of the graphite sheets42 to the dimensions of the elevators 44 are not necessarily drawn toscale.

As illustrated in FIG. 14, the graphite sheets 42 may zigzag along theplane 63 substantially parallel to the heat spreader 28 such that thegraphite sheets 42 do not extend fully through a dimension of the heatspreader orthogonal to the plane 63 parallel to the heat spreader 28(e.g., not extend through a thickness of the heat spreader 28 to extendbetween the sides or faces of the heat spreader 28 such as contactportion(s) 30). Accordingly, elevators 44 can transfer heat or electronsbetween the faces of the heat spreader 28 (e.g., orthogonal to the plane63 substantially parallel to the heat spreader 28).

As illustrated in FIG. 15, a graphite sheet may zigzag along the plane63 substantially parallel to the heat spreader 28 such that the graphitesheet 42 extends fully through a dimension of the heat spreaderorthogonal to the plane 63 parallel to the heat spreader 28 (e.g.,through a thickness of the heat spreader 28 to extend between the sidesor faces of the heat spreader 28 such as contact portion(s) 30).Accordingly, heat or electrons can be transferred in an orthogonal ornormal direction relative to plane 63 as discussed herein (e.g., betweencontact portion(s) 30) with less or without elevators 44. As illustratedin FIG. 15, the heat spreader 28 may still use elevators 44 to enhanceheat or electron transfer as discussed herein.

As illustrated in FIG. 16, the graphite sheets 42 may zigzag along theplane 63 substantially parallel to the heat spreader 28 such that thegraphite sheets 42 do not extend fully through a dimension of the heatspreader orthogonal to the plane 63 parallel to the heat spreader 28(e.g., not extend through a thickness of the heat spreader 28 to extendbetween the sides or faces of the heat spreader 28 such as contactportion(s) 30). The pattern of curvature of the graphite sheets 42 maybe such that the graphite sheets 42 extend through a substantial portion(e.g., a majority of the thickness orthogonal to the parallel plane 63of the heat spreader 28). Relatively shorter elevators 44 a notextending through the length of the heat spreader 28 can be provided toeffectively transfer heat or electrons between the graphite sheets 42 asdiscussed herein. As illustrated in FIG. 14, the heat spreader 28 canalso include elevators 44 b as discussed herein that extend through thethickness of the heat spreader 28.

FIG. 17 illustrates an embodiment of a heat spreader 28 with athermal/electrical substrate 68. The substrate 68 can be a metallicmaterial having sufficient and/or desirable thermal and/or electricalproperties as discussed herein. For example, the substrate 68 can bealuminum, copper, etc.

One or more graphite sheet 42 can be disposed around or on the substrate68. The number of graphite sheets 42 disposed around the substrate 68can be determined based on desired thermal/electrical characteristics.For example, the graphite sheets 42 disposed on the substrate 68 canfunction as a thermal interface material which can contact or connectwith the substrate 68 in any suitable manner as discussed herein.

In some embodiments, a single graphite sheet or layer 42 can be disposedon the substrate 68. As illustrated in FIG. 17, the graphite sheet 42can be disposed, be positioned, or extend around a majority or at leasthalf of the cross-sectional or side perimeter of the substrate 68 shownin FIG. 17. The graphite sheet 42 can extend around one, two, three, orfour sides of the substrate 68 such that the graphite sheet 42 extendsaround at least half of the perimeter of the substrate 68. The graphitesheet 42 can be a continual or monolithic layer or piece around thesubstrate 68, including at the corners of the substrate 68 asillustrated in FIG. 17. In some embodiments, the graphite sheet 42 maybe discrete pieces positioned about the substrate 68 with breaks at, forexample, the corners 68 of the substrate.

As illustrated in FIG. 17, the heat spreader 28 can be disposed orpositioned between battery cells 12 as discussed herein. The heatspreader 28 can have a fin 26 with a TED 20 attached to the fin 26 asdiscussed herein. The TED 20 can heat or cool the battery cells 12 viathe heat spreader 28 as discussed herein. In some embodiments, a voltagespreader 50 or voltage source 62 as discussed herein can be connected tothe heat spreader 28. The graphite sheets 42 disposed on the substrate68 can function as resistive heaters as discussed herein. The graphitesheets 42 can have breaks 64 as discussed herein to increase theresistance heating capacity. The heat spreader 28 can have any othersuitable functionality or components as discussed herein for heatspreaders, including for example connection 46, connection 48, voltagespreader 50, dovetail 58, voltage source 62, component 61, etc.

In some embodiments, a voltage source 62 can be in electricalcommunication with the substrate 68. The substrate 68 can be of amaterial (e.g., metallic) that has a higher electrical resistance thanthe graphite sheets 42. Accordingly, when the battery 14 is heated, theelectric current is passed through the substrate 68 to heat the batterycells 12. When the battery 14 is cooled, electric current is run throughthat TED 20 in a desired polarity such that the main surface 22 of theTED 20 transfers heat away from the graphite sheets 42. As discussedherein, the graphite sheets 42 may have a greater thermal conductivityrelative to the substrate 68. The embodiment as illustrated in FIG. 17may provide effective cooling to the battery cells 12 using the TED 20while having the ability to provide effective heating to the batterycells 12 using the substrate 68 as a resistive heater.

As discussed herein, in some embodiments, the incorporation of elevators44 into the pyrolytic graphite sheets 42 or surfaces increases thethermal contact conductivity or decreases the thermal contactresistivity between the graphite sheets 42 and the TEDs 20, device underthermal management (e.g., electrical components, battery 14, batterycells 12) and/or interstitial material (e.g., thermal grease)).

In some embodiments, the Pyrolytic graphite and/or graphite metalcomposite sheets or 42 surfaces are directly coupled or contactingsurfaces or portions of the electrical components (e.g., cells 12)and/or TEDs 20. In some embodiments, the surfaces of each are indirectlycoupled or contacting each other via interstitial material (e.g.,thermal grease). In some embodiments, the surfaces of the graphitesheets 42, graphite metal composite, electrical components (e.g., cells12) and/or TEDs 20 are finished to increase thermal contact conductivityand/or decrease thermal contact resistivity between them.

In certain embodiments, advantages of providing or implementing such agraphite (e.g., Pyrolytic) heater/heat sink include, but are not limitedto:

-   -   The possibility of thermoelectric cooling and high power        resistive heating    -   Saves cost    -   Light Weight    -   Withstands high temperatures    -   Simple, Reliable    -   Can be die cut and adhesive backed (e.g., graphite cut in        irregular shapes)    -   Relatively high thermal conductivity (e.g., relative to metals)    -   Environmentally friendly (pure carbon and metal)

In certain embodiments, advantages of providing or implementing aheater/heat sink battery thermal management application or systeminclude, but are not limited to:

-   -   No heat sink/heater flatness concern due to flexibility and        thickness    -   Heating enables lithium ion start-stop battery pack to be        downsized (e.g., less total battery cells), saving cost and        weight    -   Improves low temperature performance and enables start-stop        batteries to be more competitive with lead acid battery    -   Thermoelectric cooling enables lithium ion start-stop batteries        to be a drop in replacement of lead acid batteries and thus more        competitive

From a perspective of the components described herein, the combinationof thermally conductive graphite (e.g., Pyrolytic) or a graphite metalcomposite, a thermoelectric device (e.g., module, system) and a means(e.g., voltage spreader, power source) to provide a voltage differentialacross the graphite or a portion of the graphite (e.g., sheet, surface)to provide a high capacity heating function (e.g., resistive, Jouleheating) can be applicable to many different areas of thermal managementoutside of heating and cooling automotive batteries. Automotive batterythermal management is just one specific example. Other applicable areasare, but are not limited to, electronics, energy conversion and storage,human comfort (e.g., climate-control), medical devices, aerospace, andautomotive applications.

Embodiments of Battery Thermal Management Systems

FIG. 18 illustrates an embodiment of a stack or assembly 70 of batterycells 12 and heat spreaders 28. The battery cells 12 can be stacked withheat spreaders 28 in between the battery cells 12 as discussed herein toprovide thermal management to the battery cells 12. The stack 70 can bepositioned between support plates 72. The support plates 72 can providestructural integrity as well as any desired thermalconductivity/insulation for the battery cells 12. The support plates 72of the stack 70 can be secured using straps 74.

The stack 70 of battery cells and heat spreaders 28 can be furthersecured via the connection 48. For example the connection 48 can includebolt holes that allow bolts 76 to pass all of the aligned bolt holes ofthe connections 48. The bolts 76 can further physically fix the stack 70of the battery cells in the heat spreaders 28. Any suitable connection,including as discussed herein, can be used at connections 48 tofacilitate securing the assembly 70.

A heater busbar 78 may also be secured to the stack 70 via a connectionto the support plates 72 as well as being secured to the connections 48via the bolts 76. The stack 70 can be housed within or in case by abattery case 16 as discussed herein. The stack 70 can connect, attach,mate, and/or engage with the battery case 16 in any suitable manner,including via support brackets 80 that can be attached to the supportplates 72 as well as the battery case 16.

A printed circuit board (PCB) 79 including a controller 36 as discussedherein can be attached or fixed to the heater busbar 78 as well as anyother suitable connection to the stack 70. The printed circuit board 79can be connected to the electrical connections 46 as discussed herein.The PCB 79 and/or controller 36 can be one or more controllers (thermalmanagement controller or battery controller) that control functions ofany of the BTMS 10 components discussed herein, including functionalityof the battery cell 12, battery 14, heat source and/or heatsink system32, TE thermal management system 34, power source 38, and/or sensors 40.In some embodiments, the PCB 79 and/or controller 36 can be connectedsuch that data or conditions monitored by the controller 36 can be usedto regulate and control the battery cell 12, battery 14, heat sourceand/or heatsink system 32, TE thermal management system 34, power source38, and/or sensors 40 to optimize the system efficiency.

FIGS. 19-22 illustrate an embodiment of a battery case 16 with a thermalinterface 82 and a thermal window 84. As discussed herein, in someembodiments, the connection 48 can include a tapered dovetail shape 58.The dovetail-shaped connection 58 is configured to be coupled to acorresponding female shaped dovetail coupling 86 or posterior surfaceforming the thermal interface 82 with a surface of a TED 20 to providethermal communication between the device under thermal management (e.g.,battery 14, cells 12) and a TED 20 positioned outside of the case 16.

As illustrated in FIGS. 19-22, in some embodiments, the thermalinterface 82 includes posterior surface 86 of the dovetail connection 58or coupling in thermal communication with a TED 20 via a thermal window84 or opening in the battery case 16 or shell of the electrical device(e.g., battery 14). In some embodiments, a thermally conductive materialor a thermal substrate 88 (e.g., a copper surface or plate) ispositioned in the thermal window 84 between a TED 20 and the dovetailcoupling 86. The thermal substrate 88 can transfer thermal energy in andout of the battery case 16 while providing a physical barrier into thebattery case 16 (e.g., enclosing the battery cells 12 in the batterycase 16).

As illustrated in FIGS. 10-12 and 19-22, the connection 48 can include atapered dovetail configuration 58 in some embodiments. However, theconnection 48 can include any suitable shape or configuration (e.g.,square, rectangular, polygonal, triangular). The connection 48,attachment, or coupling between the Pyrolytic graphite sheets 42 and thebattery case 16 and/or the TED 20 is not limited to a mechanicalmale-female connection or joint. Rather, the connection 48 can includeany suitable configuration or manner (e.g., adhesives, nuts and bolts,screws, nails, press-fit, or interference fit) such that they are inelectrical and/or thermal communication as discussed herein. Further,the connection 48 can be attached to the graphite sheets 42 in anysuitable manner (e.g., over-mold, press-fit).

The posterior surface 86 of the dovetail connection 58 can be in directthermal communication (e.g., surface to surface contact) or indirectthermal communication (e.g., via the copper surface 88) with a main side22 of a TED 20 positioned outside of a battery case 16 as illustrated inFIG. 22. While one TED 20 is illustrated in FIG. 22, multiple TEDs 20can be provided using methods discussed herein for greater thermalmanagement, including thermally managing individual heat spreaders 28paired with an individual TED 20 (see for example, FIG. 4). As discussedherein, thermal grease or other interstitial materials may also be usedbetween the components.

In some embodiments, the battery case 16 does not comprise a thermalwindow 84 and/or thermally conductive material in the window, as aPyrolytic graphite heat spreader and resistance heater 28 can beprovided in some embodiments without a TED 20 or TE thermal managementsystem 34.

FIGS. 23-25 illustrate an embodiment of an air duct 90 and blower 92system or assembly. The air duct 90 and blower 92 system can pull and/orpush air across a waste side or surface 24 of a TED 20 as discussedherein. As illustrated in FIG. 22, the waste side 24 of the TED 20 caninclude a waste heat exchanger 93 (e.g., an air heat exchanger). In someembodiments, duct 90 and other air flow components can be optimized orsized to reduce pressure loss across the TED 20 and/or duct 90 andprovide even air distribution or air pull.

As illustrated in FIG. 24, the air blower 92 can be attached orconnected to the duct 90 to draw or pull air across the TED 20.Integrated controls can provide a switch to either push or pull airacross the TED 20. In a cooling mode or heating mode, heated or cooled,respectively, waste air can be pulled or pushed toward or away theblower 92 and exited or allowed to escape through a blower outlet/inlet94 of the air blower 92 or through a duct outlet/inlet 96. In someembodiments, the waste air can be vented to the outside environment,outside a housing, shell or enclosure the battery 14 is positioned in,or into another conduit (e.g., waste heat removal system) connected tothe blower outlet/inlet 94 to provide heated or cooled air as needed(e.g., for heating or cooling seats and/or a passenger compartment,etc.).

As illustrated in FIG. 25, the duct outlet/inlet 96 can include flappers98. The flappers 98 can be activated (e.g., open) via a thermal diode.In some embodiments, the flappers 98 stay closed unless the blower 92 isrunning. By the flappers 98 staying closed unless the blower 92 isrunning, the waste side 24 of the TED 20 can be insulated from ambienttemperatures (e.g., heating of the TED 20 is inhibited). In someembodiments, the duct 90 can be insulated to further aid in insulatingthe TED 20.

In some embodiments, the blower 92 pulls the air across the TED 20rather than pushes. When the air is pulled by the fan or air blower 92,rather than pushed, the air does not need to travel through, forexample, the blower 92 before reaching the waste side 24 of the TED 20.The air is instead pulled across the waste side 24 of the TED 20 andexhausted at the blower outlet/inlet 94. For example, the air is notheated by the heat from the motor of the blower 92 when the air ispulled. Pulling the air can be used in the cooling mode.

In some embodiments, the blower 92 pushes the air across the TED 20rather than pulls. When the air is pushed by the fan or air blower 92,rather than pulled, the air travels through the blower 92 beforereaching the waste side 24 of the TED 20. The air is instead pulledacross the waste side 24 of the TED 20 and exhausted at the ductoutlet/inlet 96. For example, the air is heated by the heat from themotor of the blower 92 when the air is pushed to increase efficiency(e.g., preheat the air as desired). Pushing the air can be used in theheating mode. In some embodiments, if preheating the air is not desiredin the heating mode, the air can be pulled by the air blower 92 asdiscussed herein.

In the context of a vehicle, the air is not heated by the exhaust systembefore being pushed across the waste side 24 of the TED 20 when the airis pulled. In such an embodiment, the inlet for the air is near, by, or,at the heat exchangers or fins 93 of the TED 20 (e.g., outlet/inlet 96)and the outlet/inlet 94 for the air is at the blower 92. When the air ispushed, the inlet is at the outlet/inlet 94 of the blower 92 and theoutlet is near, by, or, at the heat exchangers or fins 93 of the TED 20(e.g., outlet/inlet 96). In some embodiments, when the air is pushed andthe outlet is near, by, or, at the heat exchangers or fins 93 of the TED20, an additional conduit can be provided to transport the waste heataway from the TED 20, the battery cell(s) 12, and/or battery case 16.When the air is pulled, the air can be exhausted out the outlet/inlet 96of the blower 92. In some embodiments, this reduced complexity of thesystem because the air can be exhausted out the outlet/inlet 96 withoutan additional conduit or waste heat removal system. In some embodiments,the air temperature is half a degree cooler when pulled versus pushedacross the heat exchangers or fins 93 of the TED 20.

In some embodiments, connections and controls for managing the blower 92and duct 90 can be integrated into the controller 36. In someembodiments, the PCB 79 and/or controller 36 can regulate the blower 92output to optimize the system efficiency (e.g., increase & decrease theairflow, power, or motor speed of the blower 92 to match cooling orheating requirements of the battery cells 12). In some embodiments, thePCB 79 and/or controller 36 can be connected such that data orconditions monitored by the controller 36 can be used to regulate theblower 92 output to optimize the system efficiency.

It is contemplated that various combinations or subcombinations of thespecific features and aspects of the embodiments disclosed above may bemade and still fall within one or more of the inventions. Further, thedisclosure herein of any particular feature, aspect, method, property,characteristic, quality, attribute, element, or the like in connectionwith an embodiment can be used in all other embodiments set forthherein. Accordingly, it should be understood that various features andaspects of the disclosed embodiments can be combined with or substitutedfor one another in order to form varying modes of the disclosedinventions. Thus, it is intended that the scope of the presentinventions herein disclosed should not be limited by the particulardisclosed embodiments described above. Moreover, while the inventionsare susceptible to various modifications, and alternative forms,specific examples thereof have been shown in the drawings and are hereindescribed in detail. It should be understood, however, that theinventions are not to be limited to the particular forms or methodsdisclosed, but to the contrary, the inventions are to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the various embodiments described and the appended claims.Any methods disclosed herein need not be performed in the order recited.The methods disclosed herein include certain actions taken by apractitioner; however, they can also include any third-party instructionof those actions, either expressly or by implication. For example,actions such as “passing a suspension line through the base of thetongue” include “instructing the passing of a suspension line throughthe base of the tongue.” It is to be understood that such depictedarchitectures are merely examples, and that in fact many otherarchitectures can be implemented which achieve the same functionality.In a conceptual sense, any arrangement of components to achieve the samefunctionality is effectively “associated” such that the desiredfunctionality is achieved. Hence, any two components herein combined toachieve a particular functionality can be seen as “associated with” eachother such that the desired functionality is achieved, irrespective ofarchitectures or intermedial components. The ranges disclosed hereinalso encompass any and all overlap, sub-ranges, and combinationsthereof. Language such as “up to,” “at least,” “greater than,” “lessthan,” “between,” and the like includes the number recited. Numberspreceded by a term such as “approximately”, “about”, and “substantially”as used herein include the recited numbers, and also represent an amountclose to the stated amount that still performs a desired function orachieves a desired result. For example, the terms “approximately”,“about”, and “substantially” may refer to an amount that is within lessthan 10% of, within less than 5% of, within less than 1% of, within lessthan 0.1% of, and within less than 0.01% of the stated amount. Featuresof embodiments disclosed herein preceded by a term such as“approximately”, “about”, and “substantially” as used herein representthe feature with some variability that still performs a desired functionor achieves a desired result for that feature.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations may be expressly set forth herein for sakeof clarity.

It will be understood by those within the art that, in general, termsused herein, are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced embodiment recitation is intended, suchan intent will be explicitly recited in the embodiment, and in theabsence of such recitation no such intent is present. For example, as anaid to understanding, the disclosure may contain usage of theintroductory phrases “at least one” and “one or more” to introduceembodiment recitations. However, the use of such phrases should not beconstrued to imply that the introduction of an embodiment recitation bythe indefinite articles “a” or “an” limits any particular embodimentcontaining such introduced embodiment recitation to embodimentscontaining only one such recitation, even when the same embodimentincludes the introductory phrases “one or more” or “at least one” andindefinite articles such as “a” or “an” (e.g., “a” and/or “an” shouldtypically be interpreted to mean “at least one” or “one or more”); thesame holds true for the use of definite articles used to introduceembodiment recitations. In addition, even if a specific number of anintroduced embodiment recitation is explicitly recited, those skilled inthe art will recognize that such recitation should typically beinterpreted to mean at least the recited number (e.g., the barerecitation of “two recitations,” without other modifiers, typicallymeans at least two recitations, or two or more recitations).Furthermore, in those instances where a convention analogous to “atleast one of A, B, and C, etc.” is used, in general such a constructionis intended in the sense one having skill in the art would understandthe convention (e.g., “a system having at least one of A, B, and C”would include but not be limited to systems that have A alone, B alone,C alone, A and B together, A and C together, B and C together, and/or A,B, and C together, etc.). In those instances where a conventionanalogous to “at least one of A, B, or C, etc.” is used, in general sucha construction is intended in the sense one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, or C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that virtually any disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, embodiments, or drawings, should be understood tocontemplate the possibilities of including one of the terms, either ofthe terms, or both terms. For example, the phrase “A or B” will beunderstood to include the possibilities of “A” or “B” or “A and B.”

Although the present subject matter has been described herein in termsof certain embodiments, and certain exemplary methods, it is to beunderstood that the scope of the subject matter is not to be limitedthereby. Instead, the Applicant intends that variations on the methodsand materials disclosed herein which are apparent to those of skill inthe art will fall within the scope of the disclosed subject matter.

1. A thermoelectric battery thermal management system configured tomanage temperature of a battery cell, the system comprising: a heatspreader in thermal communication with a temperature sensitive region ofa battery cell, the heat spreader comprising: pyrolytic graphite inthermal communication with the temperature sensitive region of thebattery cell, the pyrolytic graphite comprising a plurality of graphitelayers extending substantially in parallel along the heat spreader andconfigured to transfer thermal energy and electric current along a planesubstantially parallel to the graphite layers; a plurality of thermalelevators between the plurality of graphite layers, the thermalelevators configured to transfer thermal energy between the plurality ofgraphite layers and configured to transfer thermal energy substantiallyorthogonal to the plane; and a conductor in thermal communication withthe pyrolytic graphite and the plurality of thermal elevators, theconductor in electrical communication with the pyrolytic graphite toheat the battery cell upon application of electric current through thepyrolytic graphite via the conductor; a thermoelectric device comprisinga main side and a waste side, the thermoelectric device configured totransfer thermal energy between the main side and the waste side of thethermoelectric device upon application of electric current to thethermoelectric device, wherein the main side of the thermoelectricdevice is in thermal communication with the heat spreader to heat orcool the battery cell by adjusting a polarity of electric currentdelivered to the thermoelectric device; and a thermal managementcontroller configured to operate in a heating mode or a cooling mode,wherein in the heating mode, the battery cell is heated by the heatspreader transferring thermal energy to the temperature sensitive regionof the battery cell when electric current is applied to the heatspreader via the conductor, when electric current is applied to thethermoelectric device in a first polarity, or when electric current isapplied to both the heat spreader via the conductor and thethermoelectric device in the first polarity, and wherein in the coolingmode, the battery cell is cooled by the heat spreader transferringthermal energy away from the temperature sensitive region of the batterycell when electric current is applied to the thermoelectric device in asecond polarity.
 2. (canceled)
 3. (canceled)
 4. The system of claim 1,wherein the battery cell and the heat spreader are positioned in abattery case, and wherein the conductor is configured to attach to thebattery case to physically fix the heat spreader relative to the batterycase.
 5. The system of claim 4, further comprising a thermal interfaceon the battery case and configured to mate with the conductor, whereinthe conductor comprises a first mechanical connector, wherein thethermal interface comprises a second mechanical connector configured tomate with the first mechanical connector to attach the conductor to thebattery case.
 6. (canceled)
 7. The system of claim 5, wherein thebattery case comprises a thermal window configured to transfer thermalenergy in and out of the battery case, the thermal window in thermalcommunication with the thermal interface.
 8. The system of claim 7,wherein the battery case comprises a thermal substrate in the thermalwindow, the thermal substrate configured to transfer thermal energy inand out of the battery case while providing a physical barrier into thebattery case.
 9. The system of claim 8, wherein the main side of thethermoelectric device is in thermal communication with the thermalsubstrate to provide the thermal communication between the main side ofthe thermoelectric device and the heat spreader via the conductor andthe thermal interface.
 10. (canceled)
 11. The system of claim 4, furthercomprising a blower and duct assembly attached to the battery case andconfigured to push or pull air across the waste side of thethermoelectric device, wherein the thermal management controller isconfigured to optimize system efficiency such that airflow from a blowerof the blower and duct assembly is increased or decreased to matchheating or cooling requirements of the battery cell.
 12. (canceled) 13.(canceled)
 14. (canceled)
 15. (canceled)
 16. (canceled)
 17. (canceled)18. (canceled)
 19. (canceled)
 20. (canceled)
 21. A battery thermalmanagement system configured to heat or cool a battery cell, the systemcomprising: a heat spreader in thermal communication with a batterycell, the heat spreader comprising: a pyrolytic graphite sheetconfigured to transfer thermal energy and electric current along thepyrolytic graphite sheet; and a conductor in thermal and electricalcommunication with the pyrolytic graphite sheet, the conductor inelectrical communication with the pyrolytic graphite sheet to heat thebattery cell upon application of electric current to the pyrolyticgraphite sheet via the conductor, the conductor in thermal communicationwith the pyrolytic graphite sheet to transfer thermal energy to and fromthe pyrolytic graphite sheet; and a thermoelectric device comprising amain side and a waste side, the thermoelectric device configured totransfer thermal energy between the main side and the waste side of thethermoelectric device upon application of electric current to thethermoelectric device, wherein the main side of the thermoelectricdevice is in thermal communication with the heat spreader to heat orcool the battery cell by adjusting a polarity of electric currentdelivered to the thermoelectric device, wherein the battery cell isheated by the heat spreader transferring thermal energy to the batterycell when electric current is applied to the heat spreader via theconductor, or when electric current is applied to the thermoelectricdevice in a first polarity, or when electric current is applied to boththe heat spreader via the conductor and the thermoelectric device in thefirst polarity, and wherein the battery cell is cooled by the heatspreader transferring thermal energy away from the battery cell whenelectric current is applied to the thermoelectric device in a secondpolarity.
 22. (canceled)
 23. (canceled)
 24. (canceled)
 25. (canceled)26. (canceled)
 27. (canceled)
 28. (canceled)
 29. (canceled) 30.(canceled)
 31. (canceled)
 32. (canceled)
 33. (canceled)
 34. (canceled)35. (canceled)
 36. (canceled)
 37. (canceled)
 38. (canceled) 39.(canceled)
 40. (canceled)
 41. (canceled)
 42. (canceled)
 43. The systemone of claim 21, wherein the heat spreader further comprises a metallicsubstrate in thermal communication with the pyrolytic graphite sheet,wherein the pyrolytic graphite sheet is in thermal communication withthe battery cell such that the pyrolytic graphite sheet functions asthermal interface between the battery cell and the metallic substrate.44. The system of claim 43, wherein the pyrolytic graphite sheet extendsalong a surface of the metallic substrate on at least two sides of themetallic substrate.
 45. (canceled)
 46. (canceled)
 47. The system ofclaim 43, wherein the battery cell is heated by the heat spreadertransferring thermal energy to the battery cell when electric current isapplied to metallic substrate via the conductor.
 48. (canceled)
 49. Aheat spreader assembly for managing temperature of an electrical device,the heat spreader assembly comprising: a graphite sheet in thermalcommunication with an electrical device, the graphite sheet configuredto transfer thermal energy and electric current along the graphitesheet; and a conductor in thermal and electrical communication with thegraphite sheet, the conductor in electrical communication with thegraphite sheet to heat the electrical device upon application ofelectric current to the graphite sheet via the conductor, the conductorin thermal communication with the graphite sheet to transfer thermalenergy to and from the graphite sheet, wherein the electrical device isheated by the graphite sheet transferring thermal energy to theelectrical device when electric current is applied to the heat spreadervia the conductor, and wherein the electrical device is cooled by thegraphite sheet transferring thermal energy away from the electricaldevice.
 50. The assembly of claim 49, further comprising an otherconductor in thermal and electrical communication with the graphitesheet, wherein the electrical device is heated when electric current isapplied to the graphite sheet via the conductor and the other conductorsuch that electric current flows along the graphite sheet.
 51. Theassembly of claim 50, wherein the graphite sheet comprises a first sideand a second side, the first side substantially opposite the secondside, and wherein the conductor is on the first side, and the otherconductor is on the second side.
 52. The assembly of claim 50, whereinthe other conductor comprises an electrical junction configured toelectrically connect to a printed circuit board comprising a controllerconfigured to manage temperature of the electrical device, theelectrical junction configured to deliver electric current to the heatspreader.
 53. (canceled)
 54. (canceled)
 55. (canceled)
 56. (canceled)57. (canceled)
 58. (canceled)
 59. (canceled)
 60. The assembly of claim49, wherein a thermoelectric device is in thermal communication with thegraphite sheet, wherein the electrical device by the graphite sheet whenelectric current is applied to the thermoelectric device in a firstpolarity, and wherein the electrical device is cooled by the graphitesheet when electric current is applied to the thermoelectric device in asecond polarity.
 61. The assembly of claim 49, wherein the graphitesheet comprises a break in covalent bonds in the graphite sheet, the cutconfigured to increase a travel path for electric current through thegraphite sheet to increase resistive heating capacity of the graphitesheet.
 62. The assembly of claim 49, wherein the graphite sheet iscrinkled to increase a length of the graphite sheet, the increasedlength of graphite sheet configured to increase a travel path forelectric current through the graphite sheet to increase resistiveheating capacity of the graphite sheet.
 63. The assembly of claim 49,wherein the conductor extends substantially an entirety of a dimensionof the graphite sheet to provide structural integrity to the graphitesheet.
 64. The assembly of claim 49, further comprising at least oneother graphite sheet in thermal and electrical communication with theconductor, wherein the conductor is in electrical communication with theat least one other graphite sheet to heat the electrical device uponapplication of electric current to the at least one other graphite sheetvia the conductor, the conductor in thermal communication with the atleast one other graphite sheet to transfer thermal energy to and fromthe at least one other graphite sheet.
 65. The assembly of claim 64,wherein the graphite sheet and the at least one other graphite extendsubstantially in parallel in the heat spreader assembly.
 66. Theassembly of claim 64, further comprising a thermal connector between thegraphite sheet and the at least one other graphite sheet, the thermalconnector configured to transfer thermal energy between the graphitesheet and the at least one other graphite sheet.
 67. (canceled) 68.(canceled)
 69. (canceled)
 70. (canceled)
 71. (canceled)
 72. (canceled)73. (canceled)
 74. (canceled)
 75. (canceled)
 76. A method ofmanufacturing a battery thermal management system for heating or coolinga battery cell, the method comprising: thermally connecting a heatspreader to a battery cell, the heat spreader comprising: a pyrolyticgraphite sheet configured to transfer thermal energy and electriccurrent along the pyrolytic graphite sheet; and a conductor in thermaland electrical communication with the pyrolytic graphite sheet, theconductor in electrical communication with the pyrolytic graphite sheetto heat the battery cell upon application of electric current to thepyrolytic graphite sheet via the conductor, the conductor in thermalcommunication with the pyrolytic graphite sheet to transfer thermalenergy to and from the pyrolytic graphite sheet; and thermallyconnecting a main side of a thermoelectric device to the heat spreaderto heat or cool the battery cell by adjusting a polarity of electriccurrent delivered to the thermoelectric device, the thermoelectricdevice configured to transfer thermal energy between the main side and awaste side of the thermoelectric device upon application of electriccurrent to the thermoelectric device, wherein the battery cell is heatedby the heat spreader transferring thermal energy to the battery cellwhen electric current is applied to the heat spreader via the conductor,or when electric current is applied to the thermoelectric device in afirst polarity, or when electric current is applied to both the heatspreader via the conductor and the thermoelectric device in the firstpolarity, and wherein the battery cell is cooled by the heat spreadertransferring thermal energy away from the battery cell when electriccurrent is applied to the thermoelectric device in a second polarity.77. (canceled)
 78. (canceled)
 79. The method of claim 76, furthercomprising positioning the battery cell and the heat spreader in abattery enclosure and connecting the conductor with the batteryenclosure to secure the heat spreader to the battery enclosure.
 80. Themethod of claim 79, further comprising connecting a thermal interface tothe battery enclosure, the thermal interface configured to mate with theconductor, wherein the conductor comprises a first mechanical connector,wherein the thermal interface comprises a second mechanical connectorconfigured to mate with the first mechanical connector to attach theconductor to the battery enclosure.
 81. (canceled)
 82. The method ofclaim 79, further comprising positioning a thermal window in the batteryenclosure, the thermal window configured to transfer thermal energy inand out of the battery enclosure.
 83. The method of claim 82, furthercomprising connecting a thermal substrate to the battery enclosure inthe thermal window, the thermal substrate configured to transfer thermalenergy in and out of the battery enclosure while providing a physicalbarrier into the battery enclosure.
 84. The method of claim 83, furthercomprising thermally connecting the thermoelectric device with thethermal substrate to thermally connect the thermoelectric device to theheat spreader.
 85. The method of claim 79, further comprisingpositioning the thermoelectric device outside of the battery enclosure.86. The method of claim 79, further comprising connecting a blower andduct assembly to the battery enclosure, the blower and duct assemblyconfigured to push or pull air across the waste side of thethermoelectric device, and further comprising connecting a blower in theblower and duct assembly, the blower configured to optimize systemefficiency such that airflow is increased or decreased to match heatingor cooling requirements of the battery cell.
 87. (canceled) 88.(canceled)
 89. (canceled)
 90. (canceled)
 91. (canceled)
 92. (canceled)93. (canceled)
 94. (canceled)
 95. (canceled)
 96. (canceled) 97.(canceled)
 98. (canceled)
 99. (canceled)
 100. (canceled)
 101. (canceled)102. (canceled)
 103. (canceled)